How can I color correct my digital photos if I don't see colors well?

June 9, 2009 7:08 PM

I want to color correct my digital photos, but I have a color vision deficiency. Up to now, I've been correcting the levels manually, but relying on the auto-color features in Picasa or Photoshop for colors, but often this doesn't do a good job and the colors look off, even to me. I can manually correct the levels and adjust the colors so they look right to me, but that doesn't guarantee they will look right to others. Is there any way to color correct numerically (for instance, using the eyedropper tool on someone's face to to see if the RGB value of skin falls within a skin-tone range) Otherwise, is there a service that I can send my digital photos to where they can color correct them perfectly and send them back? I'm interested in the digital files, not in getting prints.
posted by anonymous to computers & internet (7 comments total)

Does your tool have a "grey" setting in the colour balance dialog? (I'm not a Picasa or Photoshop user.) The GIMP's color adjustment tool has a "grey" picker, clicking it on any grey object in the image (including black and white) adjusts the colour balance to make what you picked a grey (keeping the same luminosity).
posted by phliar at 7:26 PM on June 9

Dan Margulis writes about color correcting "by the numbers".

Just as a side note, I didn't like the color of the reproductions in the book I read, The Canyon Conundrum, and the techniques are kind of print/CMYK oriented, but I did find it interesting.
posted by JulianDay at 7:38 PM on June 9

You need to read Dan Margulis's books. I'm mildly color-blind, and get natural colors for almost anything using his ideas.
posted by notsnot at 8:07 PM on June 9

The feature you're looking for is called "white balance" (this is what phliar describes). You click on a bit of the photo that is neutral (i.e. white or grey) and the software figures out the colour correction. The best way to do this is to deliberately take a picture containing something white (a coffee can lid or coffee filter is often used) whenever there's a change in the light (e.g. you move from sunlight to a room lit by incandescent lights). Then once you work out the white balance setting for that shot, you can apply it to all the other photos that were shot in the same light. You can do this either in camera, or in software after the shots have been taken.
posted by primer_dimer at 1:32 AM on June 10

1) You should be shooting RAWs instead of JPGs. Once you have JPGs is kind of too late to do serious color corrections. In fact, RAW shooting is mostly of benefit because it lets you do color corrections fairly easily.

2) You need a white balance card. I have a WhiBal that I use. Once you shoot a reference shot with the WhiBal in it, it's just a matter of setting the grey level in the raw converter which is usually just a shift click on the whibal card. You'll then need to tell the raw converter to use that color profile for all similar shots. It doesn't have to be a WhiBal balance card. Any chunk of neutral grey should work fine for most of what you need to do.

3) Corrected color can still look wonky depending what you are trying to do. I often just half-correct so it at least approaches the natural color of the scene.

4) Once you get experience with this you might just forgo it all anyway. I kind of got used to it and can eyeball what the color temp should be based on what I was shooting: sunny, florescent, dank basement, whatever. I set the color temp slider just move on. It is very easy to get caught up in every little adjustment you can make with digital photography.
posted by chairface at 4:37 AM on June 10

Correcting color balance in Photoshop –

Use RGB image. Open the Curves palette (Image: Adjustments: Curves). Move your cursor to an area that should be a neutral gray. Command-shift-click (Mac) on the gray in the picture, which will put a point on each of the individual RGB curves – the input value.

Look at the Input value for each separate curve. Take the number that is in the numerical middle (If R=147, G=175 and B=198, use the 175.) Change the Output value on the R and B to 175. This should render a better color rendition.

You may need to do this with several points – midrange tone, and lighter and darker.

Hope this makes sense.
posted by malchick at 10:04 AM on June 10

You could send them to a place like Lavalu.
Typically for wedding photogs, but I'm sure they'd do a fine job w/ your stuff.
posted by Lukenlogs at 7:28 PM on June 14