Re: [Gimp-user] [Gimp-developer] Test images and test suite (was Re: GIMP should fork babl and GEGL)

[Pat David <patdavid gmail com>]

I can't add much to the color discussion, but at least I can offer up just
about any of my images as RAW for any testing (just about everything I
shoot is cc-by-sa usually).  If anyone finds one of mine they would like,
just let me know and I'd be happy to provide the camera raw file.

On Fri, Nov 7, 2014 at 1:24 PM, Elle Stone <ellestone ninedegreesbelow com>
wrote:

> On 11/07/2014 10:25 AM, Jehan Pagès wrote:
>
> > > A good test suite of "copyleft" images would be a nice thing to have,
> > > > whether for testing new and existing editing algorithms, or for whatever
> > > > testing that individual GIMP users might want to do on their own
> > > > (printer-related, for example).
> > That's a good idea. What kind of images would be the most interesting?
> > Basically should that be images, taken with a good digital camera, of
> > a lot of objects of various colors?
> > It could also be images with color gradients, I guess (sunset/rise and
> > such)?
> > Or do you already have such copyleft images at your disposal that you
> > could provide?
> > Indeed if we could gather these for access to anyone as reference
> > (then various software could use them for their own tests), it would
> > be great.
> >
> > Jehan
> Nicolas Robidous's test image collection is very nice, in particular the
> baby's face and the brightly colored buildings make great test images. His
> images are already converted to sRGB, which means they can't really fully
> exercise the color gamuts of reasonably decent printers and wider gamut
> displays.
>
> I can make available "straight from the camera interpolated raw file, no
> enhancements added" images of very saturated (outside the sRGB color gamut)
> natural objects, mostly flowers.
>
> I've also put together various artificial color ramps, granger rainbows,
> stepped gray scales, and such. And I have IT8 target shots from several
> cameras, which I think the photographers would release under an appropriate
> license.
>
> I wish that I had a nice set of pictures of people's faces, young to old,
> male and female, of diverse skin colors. Skin tones are something that
> everyone wants to get "just right", so faces make great test images. Such
> photographs ideally would be shot raw under natural daylight, more or less
> full frame, and properly white balanced, preferably with a white balancing
> object discretely placed somewhere in the image frame (styrofoam cups, PVC
> plastic, white coffee filters all work really well, often as well as
> commercially available white balancing aids).
>
> High quality images with good gradients would be a nice addition to a
> collection of test images. Interpolated raw files that have been output in
> a wider gamut color space would be more versatile than images that have
> already been converted to sRGB.
>
> Here are links to some sample collections of copyrighted test images:
>
> http://www.pcstats.com/articleimages/200601/samsungspp2040_300dpi1.jpg
>
> I would love to have enough copyleft images to put together a copyleft
> composite similar to the one in the above link.
>
> http://www.northlight-images.co.uk/article_pages/test_images.html
>
> http://www.outbackphoto.com/printinginsights/pi048/essay.html
>
>
> Thinking more about "what kind of images", it depends on who's testing
> what. Here are some possible reasons for wanting test images:
>
> * Testing scaling algorithms.
>
> * Testing ICC profile conversions from wider gamut color spaces to printer
> profiles and/or to display screen profiles.
>
> * Testing the quality of prints made by a commercial or personally owned
> printers.
>
> So the first question is: What kind of test images, for what kinds of
> testing, do you all, as a diverse group of GIMP users and developers, wish
> you had access to?
>
> Elle
>
>
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-- 
pat david
http://blog.patdavid.net