Showing posts with label howto. Show all posts
Showing posts with label howto. Show all posts

23 September 2020

Installing a Brother HL-1222WE printer on Linux (Fedora)

I hoped I left printing and wasting paper behind me long ago, but here the COVID quarantine and online school (my daughter is first grade) forced me to buy a printer.

A bit of market research for a home printer pointed me to Brother HL-1222WE, the main pros were:

  • relatively cheap price for a laser printer with wireless connectivity;
  • cheap consumables, replacement toner cartridges are available (and I uderstand you can even refill them yourself);
  • no chip on the cartridge
  • easy to install on Linux (beforehand I read you need some proprietary drivers from the manufacurer)

So, with the printer in hand I connected it (via USB) to my Fedora desktop. It was recognized and the installation went smoothly click-click-click using the available Open Source drivers. Then tried wirelessly on the laptop, equally smooth. Below are a few screenshots for illustrative purpose:

brother printer linux
brother printer linux
brother printer linux
brother printer linux
brother printer linux
brother printer linux

To be fair, you can install the same with a few clicks and available drivers on Windows too. Only for the Android phone I installed some app from the manufacturer.

One thing to note: before installed on my Linux machine, the printer was already installed on a Windows PC, so its wireless setup (picking from a list the access point name) was done there. Not sure if the wizard for wireless setup would include that and I am too lazy to reset the settings only to try it now.

Update: If you think you may need the proprietary drivers for stuff like monitoring the toner level, it is not the case, you can use the web interface:

brother printer linux

12 January 2016

A post-mortem for the Romanian Wiki Loves Monuments 2015

For the foreseeable future I do not intend to return as an organizer for Wiki Loves Monuments, five years of working on the Romanian edition is enough for a person, the time has come for new blood and new enthusiasm. Myself I am burned enough. And, arguably, any community project has to attract new contributors, if not perhaps it lived its life.
Note: I won't be totally out of the picture, if there is a Wiki Loves Monuments in 2016, I will most likely contribute some pictures and if the organizers will feel a need for punctual help or want to borrow some experience, I should be available.

With this melodramatic intro over, is the time go back to the topic: a "post-mortem" is a cold analysis of a project, made after its end, looking at what worked and what didn't. The intention for it is to be as objective as possible, a learning experience for future similar projects.

Ansamblul bisericii evanghelice fortificate din Archita MS-II-a-A-15596
Ansamblul bisericii evanghelice fortificate din Archita by Silvia Nichita,
released under CC-BY-SA, winner of the Romanian competition.

The good

Having the fifth edition in a row happen and bring results in line with the previous editions is by itself a success. Is not trivial to have people volunteering to make it happen, sponsors to put money, contributors to participate... and having it work year after year.

It was also a success for the team when it managed to secure the funding, first with a sponsorship from Ixia which had put the things in motion and later a grant from the Wikimedia Foundation, which allowed for a lot of activities to take place. It was useful to have the infrastructure already set-up on Wikimedia Commons, Romanian Wikipedia and the website, which is hosted by RLUG/ProLinux, as it was useful to have Asociaţia ARCHÉ handling the money, as a legal entity (traditionally, the project is run by an informal group of people and needs such legal coverage).

~6000 images uploaded in one month (~5600 at Commons and ~400 at Romanian Wikipedia) is a success. Compared with previous years, is not the best, nor the worst, but in the international context, we are in the top third of the 33 participating countries.

At the first sight, 127 participants is kind of low compared with previous years (only 2013 was lower) and definitely under the 200 mark we hoped for. But that mark was optimistic, there are not many Romanian Free Software/Free Culture projects with so many contributors.

For the Wiki Weekend expedition we had a few empty places on the bus, but in the end there are 600 images (504 at Commons and 86 more at Romanian Wikipedia) within the expedition category, which is 10% of the total images.

Wiki Loves Monuments 2015 exhibition in Bucharest 52
Photo exhibition in Bucharest

It was for the first time we held an Edit-a-thon, so we lack terms for comparison, but any way you take it, especially for a first, is a success to have 10 participants, 702 images (628 at Commons and 74 more at Romanian Wikipedia) and 11 Wikipedia articles.

Also a first time was the new article writing contest, where 6 people added a total of 343 Wikipedia articles, most of which are stubs, but they are at least an inviting start. Lacking a reference point, I don't know how to call this other than a success.

The photo exhibition with winning images was open at F64 Cafe in Bucharest for about 3 weeks. The exhibition was quite small and its opening was pretty much an intimate event, so the impact was not impressive, but there is a chance for the situation to improve, if we stick to the plan and the exhibition will move to several other (and more visible places) in the coming months.

Also, a positive is the top 10 of winning images, this is good stuff. Not only by my subjective opinion, but also the fact that one of ours makes on the international winners list.

I left this for the last, since the social media impact is kind of a mixed bag: we ran a "photo of the day" thing for the entire duration of the contest (the month of September), which on facebook it was really weak, with a top of 22 likes for an image but on Google Plus it was much better (tenfold or better). Here I assume total responsibility for selecting and sharing the images and not spamming at all.

Wiki Weekend 2015 la Conacul Marghiloman
Wiki Weekend expedition

The bad

From the things we did badly, the most important I consider is being late to everything. We were late to apply for the Wikimedia Foundation grant, which in turn was approved even more late. Not having the funds secured, we missed to opportunity to promote the contest in advance and may be an important cause for the somewhat weaker participation. We were late in planning and announcing the expedition, and this can explain the weak participation. We were late announcing the winners and were late awarding the prizes and opening the exhibition, thus breaking a few promises. In front of the community I can't say more than I am sorry, we did poorly with this, please don't judge us too badly for it.

We also had a problem with the jury: one of its members simply became silent exactly when he was needed to do his part of the work. So at the time when we were supposed to count the notes, sort the results and publish them, we were in fact searching for replacements for that jury member. That was a human resources error and a lesson: do not rely on people who don't care about your project.

Another failure was the attempt to collaborate with a traditional photography festival. There was no synergy and my estimate is that not even 1% of our final images came as a result of it. Personally I can't tell what went wrong here, as I was not involved at all with it, I could only speculate some obvious reasons, but prefer not to do that. Much like anyone else, I also wait for a more pertinent analysis.

We had no media partners, not for the contest, not for the exhibition, not for anything. This is related to the first bad point above, being late. We didn't know in advance what we will really do, so it was not possible to forge any media partnership nor to announce our intentions in advance.

There is also a problem with the source of the incoming images: the bulk of them came from very few people. 75% of the images were uploaded by the top 12 participants, or close to 60% by the top 5, or close to 23% by an one single person. This isn't healthy at all. Consider that the top contributor by number of images, who also was a big contributor last year, due to personal issues most likely won't be available next year, it starts to look grim. If it want to continue growing, the contest must find some new audience and new participants.

Biserica Calvaria de la Cluj-Mănăștur, vedere sud-vestică, 2014
Biserica Calvaria de la Cluj-Mănăștur, vedere sud-vestică by Pan Ioan,
released under CC-BY-SA, 2nd place in the national contest, 13rd place in the international contest

The ugly

The thing is, in any human activity there will be parts that go well (the good) and parts that go not so well (the bad), but there are also parts which are frustrating and no matter how hard you work, they will happen anyway. In my Wiki Loves Monuments 2015 experience, those all were related to the community.

Now I am not a newbie to the Free Software/Free Culture communities and know well what to expect: they do mirror closely any human community, so is to be expected to encounter politics, power plays, egos, hidden agendas, individuals with total lack of social skills and such. I do have the guts to deal with them, Hell! if needed I can be a versed troll too! I'm not crying here, just listing some ugly things people can expect.

Traditionally we targeted the Romanian Wiki Loves Monuments to people outside the existing Wikipedia community, since a major goal for the project was attracting new contributors. However, this edition we tried additional things, like the article contest, which was addressed to existing contributors and even to existing heavy contributors. It went with flames, accusation of cheating and strong language. Not nice at all!

Our organizing team as a whole was blamed for not having many Wikipedia contributions. Yes, it is true that myself, I contribute occasionally and my contributions are more likely to be to Commons than Romanian Wikipedia (as an user, I prefer to read the English Wikipedia anyway) and yes, is true two of my colleagues signed-up only a year before, when they joined the 2014 organizing team and their contributions were related strictly to the contest, but you know what else is true? For five years, every single year we ran calls for help and in all those years there was one single existing contributor even who really replied and joined the team (unfortunately, for logistic reasons his contributions were limited, he lives abroad, does not use social media and such). So I had no problem replying "pleas join the team and make this happen!"

But don't imagine this is limited to the local community! One example is when I had the idea that nominating some of the pictures as quality images can be in itself some kind of reward for their contributors. I did not run the nominations myself, so I was not the one to be the most frustrated, but I observed the process. Most of the pictures are rejected with negative feedback from a number of people, who sit themselves on large numbers (sometime thousands) of average pictures labeled as "quality" (while winners of national or even international competitions are not good enough).

And don't get me started on those clueless people who start talking trash on your grant request without reading it entirely or understanding the issue...

RO IL Crama Hagianoff 10
Almost random monument image from the contest

Conclusion

I guess any such writing needs a conclusion, so I'll try to come with one: running such a project can be fun, it can be even rewarding on a personal level, but for a finite while. Fresh air and a fresh perspective are needed.

03 September 2015

How I organize my photos

Not long ago, there was a talk about how people deal with their photos: organize, edit, archive and such, and I gave then a partial answer. Why partial? Because I follow two slightly different processes, one when the photos are made for fun and the other when they are for work. Since that answer was partial and made behind a walled garden, I feel the need to expand it in a public piece. I don't pretend what I do is perfect, actually I recognize some flaws myself, but I got there after years of improvements and is not final.

As a sidenote, I do use a Linux desktop, MATE under Fedora, and almost exclusively Free Software, GIMP, darktable, ImageMagick, UFRaw, G'MIC, but what I do is pretty generic, can be done with various other tools. I may follow with another piece on using these tools.

Fun is fun

organize photos

When I talk about pictures made for fun, I mean they are not made for a paying customer, period. This can include anything from photos made for exhibitions, snapshots with the daughter, pictures for my blog, for Wikipedia and whatnot. Usually I take them with an older APS-C DSLR, a Canon 600D, but sometime I bring the FF DSLR. For the most part, I try to protect the better camera, but sometime I am lazy and grab whatever is closer or greedy and want prettier pictures.

The first thing to be noted is that for fun pictures, in the large majority of cases I shoot in JPEG. ...yes, I hear the outrage for such a blasphemy, but the truth is, JPEG is good enough for most of those pics, RAW would be a waste of space and time. When I feel the shoot is important or the light is really difficult, I do use RAW, even for fun pictures.

As a matter of discipline and to keep myself in shape, I try to take pictures as often as possible, ideally every day, and as soon as possible I download the pictures in my computer and then erase the memory cards. The camera has to be ready at any moment to take as much pictures as possible.

I do not use any fancy software to organize the pictures, just the file manager and a directory structure. Of course, it helps that the file manager, with the right plugin, can display thumbnails even for RAWs. The photos made in a day go into a folder with a name like YYYY-MM-DD, for example yesterday pics are in the folder 2015-09-02. Sometime, when I want to find the folder easier, I add a keyword, as there I have a 2015-08-14-seaside

organize photos

As soon as the pictures are downloaded, I try to process them - the next day probably others will come and the newest are always the most exciting. So, I enter the folder and delete some pictures: those which are failed or boring. I still don't delete enough (or still take too many), but I'm getting there, improving continuously (space is cheap, some will say). From the too many undeleted pictures left, I copy a few in a working folder, to be edited and then published. Every year I have a new working folder, and when there are more pictures from a certain event (say, more than 10), they go in a subfolder.

Almost exclusively I edit my 'for fun' pictures with GIMP, this is the editing software I feel the most comfortable with and the one that gives me the most control. There are not many pictures, so I can take my time with them. If there are RAWs, GIMP will call UFRaw for the import, and in the rare cases it is needed, G'MIC will provide some advanced filters. For batch operations like mass-resize or mass-watermarking, there is ImageMagick.

Speaking of watermarks, I almost never do it, but there are are a few exceptions, like the pictures which I suspect have the potential to be 'stolen' by newspapers (it happened a few times, even with watermarked pictures). I firmly believe a watermark will destroy the image, so I try to avoid that.

Again, because next day may come with another pictures, I try to publish my photos as soon as possible. Still, I don't want to spam my viewers, so sometimes there is a delay. For the photography blog, I don't post more than 4 items a day, and for photography sites (the likes of 500px) I post only once in a while. Social media is something I still have to work on: I lost a lot of readers (or at least interactions with readers) a couple of years ago, I blame the loss on posting too much and try to work on it. Publishing go hand in hand with license, so almost everything shoot for fun is published under a CC-BY-SA license: free to use, free to modify, free to almost anything.

Of course, there is archiving. From time to time (not on a schedule, mostly when I run out of space) I move the unedited pictures, with their directory structure, from the computer's hard drive to two external drives, in a manual process. The edited pictures stay on the computer for the entire year, maybe even next year. They have copies online and at least the copy on G+ is high quality (do you know Facebook destroys your pictures with aggressive compression and metadata removal?)

Flaws

As I said before, I recognize some flaws. The most important couple of them:

  • I do not have continuous backup, there is one only when pictures are moved to the external drives. What is currently on the computer is at danger of data loss. Still, they are 'for fun' pictures and I am lazy, so the loss won't be huge, only at most a few weeks of 'for fun' pictures;
  • When I am away for a while, in a trip or vacation, I can't properly process the photos, so when returning home a lot of work will pile-up. For a while I will have to process both old and new images.

Work is serious

organize photos

For work, you have to deliver the best result from a technical point of view, so when there is a paying customer I use my full frame DSLR, which happens to be a Canon 6D, a camera recognized for its good low-light performance. As for shooting, the pictures are taken as RAW and JPEG. JPEG is there as a backup, while the RAW is the one to be edited. Here I need 1) to get the most possible from the pictures and 2) deal with low-light situations which happens a lot when doing event photography.

Again, as soon as I get home, I download the pictures from the memory cards. But this time I do not delete the cards, I put them in a closet, to have a backup somewhere until the processing is done. Processing the photos for an event may take up to a few weeks.

I have a different directory hierarchy for the work photos, so I copy there all the files, in a directory named after the specific client or work. If the work was an event, the first thing is to make a quick and small selection (10-20 pictures) which I edit fast and deliver the same day, as a preview. The idea is for the client to have something really fast, and if he wants to post pictures on social media while it's hot, he can post pictures from me, not some crappy phone-made images.

Then I parse the files with the file manager and its native image viewer, deleting only very few, and make a selection with images to be edited and delivered. From this selection I copy all the RAWs in a different, working folder.

organize photos

Considering the large amount of images (for a wedding it can be around 1000 pictures), editing with GIMP would be a poor option, so I use darktable instead. After a few days or weeks, depending of the size of the work, images are exported with darktable at a resolution good for large prints. Then for some images that I think need more advanced editing, I open and process them further with GIMP.

After that, I deliver to the client the images, in two sets: one at big, printable, resolution, and another resized for web use. Of course, there is no watermark in sight, the client paid for the images, they are not to be tainted in any way.

If the job requires it, then I start working on the printed album. Here the work is done with GIMP ...blasphemy I hear again? Why not use Scribus? Simple: the print shop requires sRGB JPEGs, and they do a very nice job with that. When there is to be made an engraving on the album's leather cover, I prepare it with Inkscape and save in a vector format (PDF/EPS).

Only after the printed album was delivered to the client I can consider the job done. Then I move the files (sources, edits, album pages) to the two external drives and erase the memory cards.

Of course, somewhere during this process, when I get the time, a few pictures are added to my online portfolios. I have to advertise myself, right? This time, as the images are made for the client, the license can't be a free one. Sorry for that, I wish clients open to free licenses, I would offer a discount for that.

Flaws

  • Since there is a lot of time from when the pictures are taken and until I get them in the backup system, for a while the memory cards are the backup. I could probably change that and save them faster;
  • I still have a lot of work to do with promotion.

organize photos

13 May 2015

FREE Firefox?

Let's assume one is a "normal" Firefox user, so based on Windows and with no knowledge about using directly the mirrors (or without intimate knowledge of obscure acronyms). And let's assume the same person wants a FREE web browser, one with no binary blobs, with source available and not blocking the content from its user.

The challenge is, going from the Firefox start page, find a way to download the FREE version, without using external websites (so no Google search).

free firefox 38

Answer: Expand the menu thingy at the top, then go to the About page, then to the blog and find there an apologising post with a deep-buried link inside.

11 February 2015

Kdenlive video formats export

A few years ago I used to regularly publish videos, so back then I started with an evaluation of FOSS video editors available for Fedora. At the time I decided the "winner" to be Kdenlive (at the time PiTiVi was useless, OpenShot unavailable and Blender unknown for its video editing capabilities), despite all the drawbacks of its KDE interface and sudden crashes.

Fast-forward, about a year ago, I needed again some video editing, this time for a home project. Not wanting to deal with KDE again (I don't want to flame KDE, I just find a GTK2 interface more friendly to use and GTK apps integrate better in my desktop), I tried OpenShot and it worked good enough.

Fast-forward again to current times, after upgrading my desktop to Fedora 21 (from F18, no less!) I needed again a video editing task, I fired-up OpenShot but it refused to cooperate (something related to creating a video clip from a sequence of images, something I used it for before), so back to the old friend Kdenlive again.

Yes, Kdenlive can do the work just fine, it just had an unintuitive UI annoyance that had me searching the web to learn where to find a simple option (I was not seeing a tree for the forest). You open the render window and there are not many formats to pick from besides MP4, MPEG-2 and Matroska. Where are the others? Not gone, but hidden behind a "Destination" drop-down.

kdenlive video formats export

I can see why they decided to split the list in smaller sections, it can be quite long, however 1: I didn't see the drop-down and surely many others don't and 2: categories are totally arbitrary: MKV is a file, AVI a media player and WebM a website? Why? Fortunately, you can add them as Favorites or learn their place quite fast (unfortunately,after you close the app and open it again, it will default again to File rendering instead of Favorites)

kdenlive video formats export

Some other issue that made me lose a lot of time is related to video quality. At first I created a video with the default format, which is MP4 with H.264, which from what I tried later is the thest regarding file size / image quality (didn't try WebM, it isn't useful for my client here, who is the type of person using Internet Explorer on Windows 8, so it has to work OOTB). Then I tried to find a set of settings for MPEG2 or AVI/XVid close to it. No luck! By trial and error (which means rendering the video again and again) I settled for one while the file size is not that large (only ~2.5X time larger) and image quality not absolutely horrible (note: my personal projects always default to WebM).

kdenlive video formats export

30 April 2014

Pop Art

Recently I took a very colorful and quite abstract picture, which I thought would make for an interesting 'pop art' effect. The process is really basic and obvious, but I decided to share it for anyone who want to learn a quickie.

pop art gimp

So, I opened the image with GIMP. Since I want the final collage as a 4x4 composition, increase the Canvas Size to 200% on both directions.

pop art gimp

Then Duplicate the image layer.

pop art gimp

Repeat the duplication until there are enough pieces to cover the image. I need 3 duplicates, for a total of 4 pieces.

pop art gimp

Select each piece and with the Alignment Tool move them to cover the image (one right, one bottom, one right and bottom).

pop art gimp

Now the aligned pieces should fill the entire image.

pop art gimp

Leave one layer as is (if you really want, you can edit it too) and for the second open the Hue-Saturation dialog.

pop art gimp

Move the Hue slider left or right until you are happy with the new color set.

pop art gimp

Repeat for the other layers until you have something like this:

pop art gimp

Export and you are done:

pop art gimp

Here's a different use case for a similar effect: I had a single background for the water drop photos, but adjusting the Hue made it appear the pictures are more different than in reality.

pop art gimp

PS: as someone told me, I should print this at some big size and try to sell my 'pop art' creation for a ginormous amount of money.

22 April 2014

Pseudo-HDR editing

Usually I don't edit much my landscape photos, not because I don't know how but I prefer them this way. Still, recently I felt the need for some more advanced processing for a picture, it enjoyed some success so I decided to share the process. The tools used were UFRaw (in the form of the GIMP plugin), Luminance HDR and, of course, GIMP.

I passed by this scene in the nearby park at the "golden hour" and it looked photogenic, but I wanted to make it more dramatic. One can increase the drama in a landscape photo by using a HDR treatment, but not having the tripod with me (for a proper HDR image you need at least 3 images with exactly the same scene but different exposures) I decided to go for pseudo-HDR. For this, I set the camera recording mode to RAW.

pseudo hdr

Note: the real purpose of a HDR image is to have details both in the shadows and in the highlights, beyond what the camera sensor can record, the improved drama is a side effect.

The RAW image was imported in GIMP via the UFRaw plugin 3 times: with normal, -1 and +1 exposure. If you really want, you can try doing the same starting from a single JPEG an simulate the exposure bracketing with color levels/curves, but I wouldn't advise: if from a RAW you can recover some lost image details, in JPEG they are gone forever.

pseudo hdr

The result is 3 JPEG images, one under-exposed, one exposed properly and the other over-exposed, which are to be combined in a HDR. For more drama, you can bracket with more than one step.

pseudo hdr

I imported the JPEGs to Luminance HDR and set their exposures manually to -1, 0 and +1 (or whatever values you used for RAW development). Then just press "Next" a few times, there is no need to adjust parameters, nor align the images (they were obtained from the same source).

pseudo hdr

Now we have a High Dynamic Range image, which can't be used or viewed as-is on a normal computer display, it has to be converted back to Low Dynamic Range, but optimized for what do we want from it (details in shadows and/or highlights, drama, whatever).

pseudo hdr

Time to pick one of the presets in the right column, one you think is the best for your case.

pseudo hdr

Then I adjusted the color levels a bit (if you prefer, the levels can be adjusted later with GIMP or any other image editing app).

pseudo hdr

Now the image can be exported as a JPEG benefiting from the HDR/pseudo-HDR treatment. You can leave it as-is if you like.

pseudo hdr

However, I opened it again with GIMP for more refinement: sharpening and color curves adjustment, to make the colors warmer. This is my end result.

pseudo hdr

18 March 2014

DPI and photography

There is a good understanding of DPI among hardware geeks (they may boast about how superior is tablet X due to a higher DPI display), still I am surprised to see how many people from the photography world do not understand this (sometime don't want to learn, on the "is technical stuff, I am an artist and not care about technical details") to the point it becomes ridiculous, so I will try to explain it with simple words, in case someone will pay attention.

DPI stands for "Dots Per Inch" and is a characteristic of a hardware device (for example a computer/tablet/phone display). It says how many pixels are in one inch (1 inch = 2.54 cm). Example: the computer I use to write this piece has a 38 cm wide display, which is 38 cm / 2.54 ~= 15 inches. Considering the horizontal resolution is 1600 pixels, then it has a resolution of 1600 pixels / 15 = 106.67 DPI. Of course, the higher the DPI value, the better looking the image will be on your display, as it will enable to to see finer details.

dpi screen
In digital photography the situation is different: your photo is a file and it can be put on a wide range of displays. The DPI value is not as important as the actual image resolution in pixels, it is actually metadata. Actually the correct term when talking about photos is PPI, standing for "Points Per Inch", but PPI and DPI are close enough, is not a huge problem if you interchange them. PPI is relevant when you print the image, is the density of color points to be printed by a inch. The math is similar and having a target print size and print image quality (PPI), it will help determine the needed pixel resolution. Example: you want to print a 15 x 10 cm image at good quality (300 PPI). On the horizontal 15 cm / 2.54 = 5.9 inch, then 5.9 inch * 300 PPI = 1770 pixels. On the vertical, 10 cm / 2.54 = 3.96 inch, then 3.95 inch * 300 PPI = 1182 pixels. In conclusion, you will need a 1770 x 1182 pixels image. 1800 x 1200 is close enough and easy to remember, so a 1800 x 1200 image will print at good quality at 15 x 10 cm.
dpi print
JPEG is the file format we use day to day to exchange photos and it has the ability to store a DPI value somewhere inside its metadata, but is only metadata: an indication at which size (in cm or inches) to print the file. But you can print the same file at any dimension or any DPI/PPI value (of course, with the respective image quality consequence). Changing this value won't modify in any way the look and work of your digital file.

Now, what is a good DPI value for your print? This depends on its intended use, of course :) A 300 DPI is considered good enough for a quality print, like those in the glossy magazines, where you look closely and expect to see fine details. When printing a poster which will be seen from a couple of meters, you can lower the DPI value at 100 and for a billboard to be seen from tens of meters, you can go way lower: it does not mater the printed points are huge when looking closely, nobody will do that.

Now another practical example to illustrate the ridiculous part and how to deal with it. For a recent photo exhibition (it is still on display), the requirements were "100x66 cm at 240 DPI". This is ridiculous: 100 cm / 2.54 = 39.4 inch, 39.4 inch * 240 DPI = 9456 pixels and 66 cm / 2.54 = 26 inch, 26 inch * 240 DPI = 6240 pixels, so to satisfy it you need a 9456 x 6240 photo, which means 9456 * 6240 = 59005440 - you need a 60 Megapixel camera to produce it. Nobody in the target group for that expo has access to such a camera. What to do?

Knowing the people, I can safely say most of them just ignored a requirement they don't understand, and even if they understand can't follow. Still, some tried their best and this is the right thing to do, consider other exhibitions have sane requirements you can, and then should, follow, like the one asking for 1400 x 933 at 96 DPI.

The most obvious thing to do is to resize your image to achieve the needed resolution in both pixels and DPI (GIMP example below). This is sensible thing to do when you scale down the image, as in the 15 x 10 cm case, (reduce the pixel resolution count) and you can optimize interpolation method and post process your image. However, when it would need to scale up, as in the 100 x 66 cm case, is not only a waste of resources and time, extrapolation will lower the image quality so the result will be worse than printed at a low DPI value.
dpi print
What I do in such cases (and I got my images accepted in quite a few exhibitions) is to give the image at the largest pixel resolution I have available and then set the metadata DPI value for the desired target in centimeters, even if lower than the requirement. Is going to be the best print I can anyway.
dpi print
Most of the photos you will encounter have a value of 72 DPI, this is because that is the value assigned by default by the camera for historical reasons: it was the common resolution for computer displays when digital cameras were introduced to the market, at the time we used 14"-15" CRT monitors. I am not sure I can change it inside my Canon, but it does not matter: most of my photos are to be shown on a computer display and I can change the value (as shown above) when editing for a special print.

Of course, as I told above is specific to photography. For illustration/vector graphics is a different matter, we may talk about at another time if there will be enough interest.

27 January 2014

Nightmare wallpapers

A fan of my photos keep asking for large resolution versions of various pics (I usually put online web-optimized stuff) so I cave in, that's the explanation for me having often posts like this.
The images below are pretty-much made in camera (they were edited with GIMP only for crop, resize, BW conversion and color curves adjustment). The motion blur is created in-camera, with the following recipe (which you can learn looking at EXIF data): put a somewhat long exposure time, 1/10-1/15 of a second, start moving the camera and then press the shutter. The first and the last are made moving the camera on the vertical axis and the second by rotating the camera and zooming at the same time - pretty easy but you will need a bit of exercise to achieve a smooth movement.

nightmare wallpaper
nightmare wallpaper
nightmare wallpaper

29 December 2013

Anaglyph

Disclaimer: to properly read the following article, you need to have a pair of red-cyan 3D glasses, otherwise the images won't display as intended. The cheapest one should do it, perhaps even home made. Lacking such glasses, you can generate your own 3D images for different types of glasses.

A few weeks ago I stumbled upon an old article about how James Cameron is/was remaking Titanic in 3D and somewhere in the technical explanation it was mentioned you can do 2D to 3D conversion with Free Software tools, namely the G'MIC plugin for GIMP.

In the late '90ies I received a computer magazine which came with a pair of paper 3D glasses and a CD containing the usual software demos AND a few 3D pictures, it was my first contact with anaglyphs. I still have the glasses, but I use them maybe once every few years, when I remember to search some such images.

Along the time I learned how to properly make such images: two cameras, filters, combine the two images in one. Way too much effort for me. It looks like way too much effort even for some commercial filmmakers...

When I saw the Titanic article, I said to myself 'what the heck, let give G'MIC a try'. AFAIK it is not available in any official Fedora repo, but you can download a binary from the upstream, drop it in the proper folder and go with it. It will survive even a distro update/reinstall. Not a big fan of the 'application inside another application' approach of G'MIC, nor of its duplication of existing GIMP features, that's why didn't have it already installed, but playing is fun.

anaglyph

I don't have the time and patience to learn how to fine-tune the parameters (with hand crafted depth maps you should be able to reach high quality results), nor do I plan to return to anaglyphs any time soon, so I used pretty much the automatic settings. Below are a few pictures I think came decently with no fiddling and automatic settings:
anaglyph

anaglyph

anaglyph

anaglyph

anaglyph

anaglyph

anaglyph