Google| Subject | Re: converting raw images from Canon EOS 600D |
| From | Floyd L. Davidson |
| Date | 12/02/2013 02:49 (12/01/2013 16:49) |
| Message-ID | <87pppghvji.fld@apaflo.com> |
| Client | |
| Newsgroups | rec.photo.digital |
| Follows | bd |
| Followups | nospam (6m) > Floyd L. Davidson bd (8h & 58m) |
Hey! It's nice to see you managed to wade through the trash heap and get back with more info!
bd <bd@nospam.fr>wrote:
The above item, setting Output Depth, might be the problem with opening the TIFF files with GIMP. The latest GIMP releases just convert a 16 bit depth file to 8 bits, but earlier ones gave an error.Floyd L. Davidsonbd
Color Management -- A. Input ICC Profile: No profile B. Gamma: 0.45 C. Linearity: 0.10 D.
OutputFloyd L. Davidson
ICC Profile: sRGB E. Output intent: Perceptual F. Output Depth: 8 (16 sometimes)
Also, the TIFF related stuff is in a library, used by both UFRAW and GIMP, so it if it is something else it may not actually be related to the specifics of either of these programs!
At any rate, try both 8 bit depth and 16 bit depth. Do that with two different images, one for each bit depth. If neither can be opened, see what this does:
bdThat requires the ImageMagick package be installed. If it tells you there is no such command, you definitely want to download and install it! Great tool set for working with images.
convert image1.tif -depth 8 newimage1.tif convert image2.tif -depth 8 newimage2.tif
Then try opening those with GIMP.
And if it still doesn't work, this almost certainly will:
convert image1.tif -depth 8 -type truecolor -density 300 -units pixelsperinch newimage1.tifIf that works, try it again without the "-density 300 -units pixelsperinch" options.
What versions of UFRAW and GIMP are you using? I use, and recommend sticking with, GIMP 2.6.11. The 2.8 version is a bit of a pain. There is also the potential to download and build a custom 2.9 version, but that gets fairly involved.
The discussion above about bit depth is probably the solution, but if not run "tiffinfo" on one of the TIFF files and post the results here. Actually, post the "tiff.dat" file that results from this command:Floyd L. Davidsonbd
B. Select the output file format (I would recommend only TIFF).
This is not appropriate here. I like the TIFF format and use it a lot, but the raw data from my new camera do not seem to agree with what is expected in the tiff format. Whenever I select TIFF as output format for ufraw, I do get tiff images indeed, but I can't open them using GIMP ! The message I get is something like: GIMP message: the opening of .....tif has failed: Le greffon Image TIFF n'a pas pu ouvrir l'image (the tiff image plugin has been unable to open the image).
tiffinfo image.tif | grep -v Note: >tiff.datWhat that does is get rid of the output for "MakerNote", which is a massive hex dump of little use.
So, untill I get to know how to solve this, I have to settle with the ppm format, which seems to work fine.DCRAW defaults to an 8 bit TIFF and UFRAW defaults to a 16 bit TIFF.
NEW: I just tested ufraw with the tiff output format on an old raw image from my old Canon Powershot G2 ==>Same results ! Gimp refuses to open the sort of tiff I obtain... It worked with the tiff that I obtained using straight dcraw (dcraw -T), it does not with those I get through ufraw
I am not sure that I always went though these steps in the right order, and, so far I had never used the XCF format, which I will do from now on.Well, most of the steps are either something you'll never change, or they are things that you'll check and probably set differently with each and every set of images. It seems like a lot of stuff now, just because it's all new. After a couple weeks of constant use they will be old hat. You probably won't check them every time, but it's also true that as soom as you see the image pop up you'll remember any odd setting you changed to last time that need to be reset back to the normal default.
XCF has the huge advantage that it will save all the layers for you in a way that can be accessed again by GIMP. A very useful example would be any image where you insert text, because initially the text is in a separate layer. Save it as an XCF file with the layers as they are. Then flatten the image to remove all the layers and put everything into just one layer which you then save in whatever output format you want to use. If you later want to change the text, reloading that output file make it a real pain, but starting again with the saved XCF intermediate file makes it a walk in the park.
I had a few times used a gimp filter: Filters =>Improve =>Sharpen. It sometimes gave good results, although not as good as what you get with the jpeg images delivered by the camera. For this filter, I used the defaults settings and, each times I had tried to change these settings I got worse results.Sharpening is a bit of an art all unto itself. The amount that looks just right depends on the image content and on the image size. In most cases *all* images made with digital cameras using a Bayer Color Filter will benefit from sharpening. How to is the hard part.
Start by using Sharpen set to 40%. If you scale the image down to say 800x600 to post on the web, only use maybe 25%. If you scale the image up and want to print it at 16x20, you'll find something greater than 60% will be needed. In any case, when you use sharpen and want to see what it has done, get the Navigation window up and click on the third icon from the left at the bottom, which will magnify the screen to give you a 100% (one image pixel to one screen pixel) view of part of the image. That is the only way to reliably see what the effect of sharpen is.
And, to top that off, there is Unsharp Mask. That is a different method for sharpening an image. It works slightly different, and is probably better for images that have been scaled down in size, while Sharpen is probably better for images that are scaled up in size.
It also requires less on smallar images. Set the radius to 2.0 and the amount to 0.2 for small images, and step each up one click at a time for larger images until you like the results. Again, view the final image at 100% to see the real effect.
I just discovered something - but I surely need to investigate this a lot more :Yeah, but... the problem is that it worked for that particular image. Others may become somewhat horrible. That's the trouble any sort of a "magic box" solution. You can't tell what it is doing, and it's really hard to adjust it a little more or less.
Correct luminosity, saturation... "Click on both left and right bottom reset buttons"
If, instead of doing this above, I click to both right and left buttons that are just above the reset buttons, that is:
Black spot automatic adjustment
and
automatic adjustment of the curve (flatening the histogram)
I get a non linear curve, and the image looks a lot sharper and better, at least for this particular image which is the photo of an old handwritten document more than 200 years old and faded.
Better is to learn how to decide that you want a different gamma curve, different brightness, different saturation, and so on. Then you can adjust each one very precisely to get what you want. Of course you won't learn to do that in a week or two! It takes literally years of experience to learn how to do it in a way that looks like you have years of experience!
-- Floyd L. Davidson http://www.apaflo.com/ Ukpeagvik (Barrow, Alaska) floyd@apaflo.com
11/30/2013-
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