the digital printing house LSI has some problems with rendering grayscale illustrations correctly. The instructions given below were prepared for Photoshop users. Perhaps some kind soul can trurn them into equivalent instructions for Gimp. Then I can pass them on to the publishing community. ----------------------------------- 1) In PhotoShop (I'm using 6.0), load the grayscale picture or photo you want to print with LSI. Save it as a TIFF and adjust the image to the size and resolution you will be using in the final document (usually 300 dpi, but could be 600 dpi).
2) Select the Color Sampler tool. This will give you 4 possible eyedropper selections which, as you make them, will be listed under the Info palette. 3) (To do the following, you may want to magnify the areas you are concentrating on.) On your photo, find the lightest point, or any area you want to print as all white. Click on this with the eyedropper. Next, find the darkest point in your photo, or any area you want to print as all black. Click on this with the eyedropper. Do the same thing with the lightest area you want to print (be visible) as gray, and the darkest area you want to NOT print as all black (in other words, to have some shadow detail). Under Info palette, you should now have percentages listed for all four points. 4) Now go to Image:Adjust and select Auto Levels. See how this affects the % settings in your Info palette. You will see each original setting with the new setting to the right of it. Usually your low %'s will go down and your high %'s will go up. 5) Looking at the new settings: If your #1 point (white point) is now below 5%, then your white areas should print as white. If your #2 point (black point) is above 93%, your black areas should print as black. If your #3 point (lightest gray area) is around 10-15%, it should print as light gray. Your #4 point is not always necessary, but anything under 90% should print dark but also show some shadow detail. If the new percentages fall within these boundaries, you should be okay. If not-if either the white points or the black points are too low or too high-you can make further adjustments as follows: 6) Go to Layer:New Adjustment Layer:Curves. You'll see a box with a grid labeled "Channel: Gray." The lower left corner should be your maximum white point, and the upper right corner your maximum black point (visible on the gradient strip to the left of and below the box-if it's the opposite, you can reverse it by clicking once on the gradient strip). 7) A line runs diagonally from lower left to upper right of the box, with a small square at each end of the line. To adjust your white point, put the pointer over the lower left square and hold down the left mouse button. If you move the square along the bottom line to the right, you will see the %'s in the Info palette decrease. If you move the square up the left side of the box, you will see the %'s increase. Which direction you move depends on what changes you want to make in the %'s. Just be aware that all 4 percentages will be affected to some degree at some point. It's best to keep all your adjustments here to the barest minimum that will give you the results you want for all 4 points. 8) To adjust the black point, make the same sort of adjustment to the square at the upper right corner of the box. Again, be sure to watch how the %'s for all 4 points are affected. 9) Once you have all 4 points in the Info palette registering within the limitations you want, just save the photo. (I suggest saving it now anyway before going on to any of the next adjustments.) 10) If the above adjustments in Curves don't give you results close enough to what you want, you can play with tweaking the diagonal line that runs across the box. You can grab it (with your left mouse button) anywhere along its length and bend it up or down. You can also slide up and down it as you bend it. Watch what happens to the percentages. You can even bend it up in one section and down in another. You can put as many points along the line as you want. In fact, if you're feeling adventurous, I suggest playing with this for a while to get the feel of it, even if you're not going to use it right now. If you screw up, you can undo any of your adjustments by grabbing any point you've added to the line and sliding it along the line until it's off the edge of the box. 11) One important caveat: Don't pay attention to what your photo looks like on your screen; it may or may not look the way it will when printed by LSI. If you stick to the percentages in the Info palette, you should get the results you want. ---------------------------------------------- -- John Culleton Books with answers to marketing and publishing questions: http://wexfordpress.com/tex/shortlist.pdf Book coaches, consultants and packagers: http://wexfordpress.com/tex/packagers.pdf _______________________________________________ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
