Expert: LizaL - 10/24/2004

Question
thanks so much for the detailed info, i will give it a try, i had tried to scan at different resolutions, 300 dpi & the scanner comp. gave me a standard reply & told me to scan at 72 dpi, but they both came out the same on my screen,  i will try your advise in photoshop, however i am just learning photoshop (self taught).  but you have given very detailed instructions so i think this will help alot thanks again !
Followup To
Question -
Hi, i am trying to scan a original watercolor painting, my operating system is windows 98 p/c. & my scanner is a mustek flat bed 11" x 17". however when i scan it the colors don't come out the same as the original, they are all washed out.  is there some way to adjust the colors ?
any help will be appreciated,
thanks,
June
Answer -
Hi June,

This is the million-dollar question for which there is no hard and fast answer, I'm afraid. You don't provide a lot of info on just how you scan your images, like the resolution you use, but from everything I've read, that's not the best way to solve the problem, anyway. What I've found is that your best color correction lies in Photoshop.

I do photo retouching for a couple of professional photographers in my city, so I try to keep up on technique. Now a lot of people might tell you to bump up the resolution of the scan -- that is, make it 300dpi before it gets to Photoshop -- but that's not always the way to solve the problem.

I may indeed scan something at 300dpi, but what I retouch doesn't always stay at that high a resolution. At the editing stage, it's the tools that count. If I change the image's size, I do that last.

Anyway, for color adjustment, what I use the most are Levels and Curves. These tools can be somewhat complex, but they can help you be very exacting in your results.

Both Levels and Curves are found under the Image pulldown menu, under Adjustments. In a nutshell . . . if you have an image open and you open Levels, you'll be presented wth a histogram that represents the levels of Red, Green and Blue (for an RGB image), for example. You can edit each color's channel separately, or edit all of them at once with the RGB channel.

Right below the histogram are three Input sliders. Sliding the one on the far left increases the shadow in the image; the middle slider controls the midtones, and the right slider, the highlights. Experiment with these to see if you can adjust your colors to match your original.

The Curves dialog box brings up a grid, with a diagonal line through it, and the same selection of channels. This diagonal line is what you use to adjust the balance of color in your scan, with regard to the highlights, midtones and shadows (which are depicted in grayscale in the bar that runs along the left side of the dialog box). You can click on that line to produce a point that you can drag -- up will control the highlights, down will adjust the shadows. You can also create three points on the line, and move just the center point -- in order to "anchor" a certain area of light or shadow in your image, yet move another part of the scan's colors. (This is one of those things you have to try in order to see what I mean, LOL!)

As I said, these are very much "nutshell" explanations. Please do some reading on these tools, and experiment with your images. We could talk for weeks and not cover everything there is to know, just about these two tools!

You might also experiment with Color Balance (Image>Adjustments>Color Balance). This will let you adjust the levels of specific color in your image, and you can also change them with regard to the shadows, midtones, and highlights.

A couple of things NOT to use are Auto Levels and Auto Curves. Well, you can *try* them, but these don't provide the best adjustment with color correction. They don't "read" the information in the scan accurately, and they pretty much provide "best guesses" about the colors.

Light has a lot to do with color matching. The best light you can use is Kelvin lighting (you can read more about Kelvin and color temperature here: http://www.schorsch.com/kbase/glossary/cct.html ). But if you don't have a Kelvin-lit viewing booth at home (and most of us don't!), try to have as much natural light in your work room as possible. I usually work with the shades on both of my office windows up, and no lights on, during the day.

I've been a graphic designer for 20 years, and it's an age-old problem -- translating something to an electronic format, and then making it "match" the original. You just can't do it perfectly, unless you have the piece printed by a professional printer, on an offset press.

But we do have Photoshop, and that's not too shabby for helping the process.

Good luck and let me know how things turn out!

Lisa


Answer
Hi June!

Scanning can be frustrating! I think that's why Adobe has developed the controls in Photoshop so well -- to compensate for an imperfect way of getting images into the computer.

I hope my advice will help you as you move along with Photoshop. If you have any other questions or problems, please don't hesitate to ask, either through this site, or you can email me, too.

I taught myself Photoshop back when it was in version 2 -- I had to learn it in order to teach it, when I taught college commercial art. So I'm sure you'll be fine learning it on your own.  There are also a lot of good books and Web sites out there.

Thanks!

Lisa
lizal@little-works.com