The Creative Process of Photography | 3
The Creative Process of Photography
For output to an inkjet printer, RGB files are preferred, but if you're going to be sending your files to a commercial printer for process-color printing, your files will need to be converted to CMYK. Due to the multiple variables involved in offset printing (resolution, dot gain, paper, inks, type of press, etc.), consult with your printer before converting your files to CMYK. If the color is absolutely critical, you may want to hire an expert to do the conversions for you and supply you with color proofs before the job is printed. In any case, convert the images after you've done all of your color correction and retouching. Save the flattened CMYK file either a .TIF or .EPS formatÂand be sure to include "cmyk" in the filename, so you'll know which file is which.
When your files are converted to CMYK, you'll notice that the colors may shift slightly. That is to compensate for the more limited range of colors (called the "gamut") that can actually be reproduced on press. In the example shown above, you can see that the histograms of the two versions of the image are significantly different.
To view a "soft proof" of the CMYK image on-screen in the Proof Setup dialog, be sure to set the Profile to match the final printing process the offset printer will use. There are a number of options to choose from to replicate what the image will look like when printed sheet-fed versus web offset on coated or uncoated paper. Consult with the printer so that you know what those settings should be to give you the most accurate representation of the actual printed results.
Preparing Images for Print
I do a few last things to prepare an image for print. If the image has multiple layers, I flatten it because working with a flattened image is faster (it's smaller and Photoshop doesn't need to think about how to display multiple layers). Then I make sure the image is the correct size.
Because of the algorithms Photoshop uses for sizing images, I prefer Photoshop's Image Size command over the printer driver when resizing images. If the image needs just a slight adjustment, I'll use the Bicubic interpolation to resample the image. If it needs to be resampled up dramatically, I use the Bicubic Smoother option; for resampling down, the Bicubic Sharper. If images need sharpening after resizing, I use either the Unsharp Mask or the Smart Sharpen filter. I can also perform selective sharpening by duplicating the image onto a second layer, sharpening that layer, and then using a layer mask to reveal or hide parts of the sharpened layer.
Photoshop's Soft Proof feature allows me to simulate on-screen what the image will look like on a given output device. I can choose to soft proof for a desktop printer (using the printer's profile) or a CMYK device. I can also preview what the image will look like as a result of choosing different rendering intents. Based on the proof, I can make any necessary changes to the image.
When I'm satisfied with the proof, I select Print with Preview, which allows me to place the image on the page as well as choose how to color-manage the image. For Color Handling, I select Let Photoshop Determine Colors, choose the printer profile, and select a preferred rendering intent for my printer.
Clicking Print exits Photoshop and enters the printer driver. If you have chosen to use Photoshop's color engine to convert your image to the color space of the printer (as we did above), make sure that you have turned off any other color management features in the printer driver, or you will convert the file twice, which I can almost guarantee will not look like the soft proof when printed. For best results, make sure that you designate other important information, such as paper types and inks, in the printer driver before printing.
If I think I'll want to print the image again, I save the flattened, resized, and sharpened file with a new name, again using a naming convention such as "FSPL" for Flattened, Sharpened, on Premium Luster paper, or "FSM" for Flattened, Sharpened, on Matte paper. I then archive these images onto DVDs and my external hard drive along with the layered versions.
To set up a proof, go to View: Proof Setup, and select Custom from the menu. There are a number of different profiles from which to choose, including specific inkjet printers (such as the Epson printer in the example to the right) and commercial offset processes. You can also set the soft proof to preview what the image will look like on different electronic displays if you are tweaking your files for display on a specific type of computer monitor or for video.
Excerpted from Window Seat: The Art of Digital Photography & Creative Thinking by Julieanne Kost. ISBN 00-596-10083-3, Copyright Â© 2006 O'Reilly Media, Inc. All rights reserved.
Created: March 27, 2003
Revised: April 10, 2006