Expert: Scott Valentine - 11/11/2009

Question
I am new to the world of PMS colors and am setting up a 100-page book we will be having printed for a conference. To help on budget we now need to make it a 1-color job. I know that by picking a single PMS color (ours will be blue) we will still have all of the variations of blue all the way down to a 0% of blue for the white areas. I just don't really understand how to make my photos and other elements that PMS color....I saw an question/answer from last year where you answered a woman's problem about converting a CMYK photo into 1 color and you told her to make it grayscale and then use the Channels box to assign one as the PMS color and possibly have another one or two on, depending on the printer's instruction...so can I do the Channel thing to the entire pages in my document or do I have to do it to the individual elements before placing them? I'm SO new to this PMS world :)

Answer
Hi Katie - sorry for the delay!

If you are being restricted to one color plate, but have full-color photos, you can use any trick you want to convert to grayscale. From there, you can simply provide the printer the plate and the color specification, and they will use the gray values as density for the ink. What I described above was for converting images for a press to use CMYK plates - you have it a little easier :)

However, if you want to preview the results, you can use this handy trick: add a blank layer over your image layer and fill it with your PMS chip color. Set this new layer's blend mode to Color. If you flatten this, your printer should be able to reproduce the plate since you have a specification for the spot color.

Again, your printer should be able to tell you exactly how they need the file - it may be that you only have to provide them with grayscale RGB images, or they may want the black plate from a CMYK image, but you'd have to adjust that plate for a continuous tone.

I do recommend that you preview your images with the spot color, even if the printer will take just the grayscale image. The reason is that the ink densities may not be what you expect, and you could end up with large patches of solid areas with little or no variation. For typical monochrome use, you should start with a gray conversion that doesn't clip anything to solid black or solid white. This is especially true if you are using any kind of metallic addition to the ink (white means no ink at all, so you wouldn't see the sheen or even any tint). There are tons of choices for converting from color to B&W/gray, so try a few and see what gives you the best results. You can even put a Levels or Curves adjustment layer between the photo and color fill layers to 'tweak' the gray values for best effect.

I hope this helps you out - please let me know if you need anything else :)

-Scott