Converting color space

Discussion in 'Digital Darkroom' started by john_ashby|2, Dec 22, 2009.

  1. I recently printed a batch of pictures that looked great on my screen, but the colors were horrible as printed, a bright red sweater came out brown and all the flesh tones looks sickly.
    I showed the on-screen and print versions to a much more experienced friend who said it was probably a color space issue, and when I told him I was using prophoto, he was sure that was the problem and said just convert to sRGB before printing. When I do the conversion to sRGB, the on screen image looks very similar to what printed. Do I have to do something to bring the colors back to what I intended? I previously used the color profile supplied by my printer and it looked too green on screen but I printed anyway and the prints are also too green. So this time, I just left them to auto-correct the images and still got unsatisfactory results.
    Thanks.
     
  2. How are you doing the conversion?
    The colours should map to sRGB, although some might be out of gamut - the conversion process will normally find a 'good enough' match
     
  3. Why are you editing in ProphotoRGB? Why not just start off in sRGB?
     
  4. Martin, I don't have photoshop in front of me now, but I believe it was the edit menu near the bottom where it has an option like "assign color profile". I change it there from prophotoRBG to sRGB and the result on screen appears not even close to "good enough".
    David, I took a course in raw workflow over the summer and they said to use prophoto set it to prophoto in ACR to preserve as much of the color data for as long as possible. I also work in 16-bit mode space and change it to 8 bit right before saving as a jpg.
     
  5. You should never apply the printer profile to an image. This is different than your working colorspace (i.e. prophoto, sRGB, etc). If you are scanning film, then scanning in and working in ProPhoto makes a lot of sense. Many slides encompass a color range greater than sRGB and even Adobe98. If, however, you are editing digital camera files, then ProPhoto is not as usefull especially if the files were captured in the sRGB color space to begin with. I recommend converting your images to Adobe98 prior to printing. Turn OFF all color management in the printer software and let Photoshop manage the colors. Select the appropriate profile for your printer/paper combination, and assuming you have a calibrated monitor, the results should be quite similar. Remember to view the prints according to how the monitor was profiled for the most accurate results, e.g. if your monitor is profiled for 5600K, and you view your prints in the light from a north facing window, they likely will not look the same.
     
  6. Don't assign a color profile, convert it.
     
  7. John,
    what screen are you using? If you work from a laptop, this alone may be the problem, as colours never come out on a printer the way you saw them before. If you have a standalone monitor, is it calibrated? And what is your printer?
    I have had huge problems with my Epson R800, because the colours never came out as intended. My default image profile is AdobeRGB, and even with Photoshop determining colours, neither this nor a conversion into sRGB worked. Then I bought a standalone monitor which I use to work in my images (it was a laptop before), and had my printer profiled (some Epsons love reddish tones, it seems). This made the world change for me! You won't believe the difference even an only slightly altered setup may cause, let alone something like this.
     
  8. I know the problem, as I re-produced it with my pic.
    You did "assign profile", which leaves the color numbers and just gives it a new tag. This doesn't work. You need to "convert to profile" which moves the ProPhoto color numbers to the "sRGB" color numbers. See http://www.adobepress.com/articles/article.asp?p=1315593&seqNum=6
    I am now confused on one point though. The "working space" (edit, color settings) doesn't seem to change when you do a "convert to profile". So let's say you're working space is ProPhoto and your image color profile is ProPhoto. You convert to sRGB. But the working space remains as ProPhoto. Not sure what that implies. I point it out just as a note of caution as I don't know if this means you have to ALSO change your working space. Maybe someone else can answer this.
     
  9. What Alan said. When you have an untagged image and you know or suspect what the color space is, you can assign a profile, so the image can be used in a color-managed workflow. If you know what color space an image is in, you certainly don't want to assign something else. It is fine to work in ProPhotoRGB as long as it is 16 bit. If your printing setup is correct, you should get a good match printing that 16 bit ProPhoto image. If not, something is set wrong. If you want to convert the image to a smaller color space before printing, e,g. AdobeRGB or sRGB, do the convert to profile step before reducing the bit depth. To get more help, you need to provide more information (printer driver and Photoshop settings, monitor calibration, etc.)
     
  10. Does anyone know what working space then means if it is not the same as the photo's color profile? It doesn't seem to make sense that these would ever be different, no?
     

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