There has been much interest in the past few months about the various workflows used to print Quadtone inks through various Epson printers. In this article I hope to clear up some of the confusion (rather than adding to it, starting with the simplest workflow I know and then covering more advanced ones. These suggestions are for the Epson 3000 and 1200, but can be adapted easily to the other 4 and 6 color printers.

First, some general suggestions. Test the paper and the ink. How? I use Epson's 4x6 ink jet card stock, 4x6 photo paper or cut the paper I want to test into 4x6 size(the 4x6 inkjet card stock is very close to Sommerset Photo Enhanced in its printing characteristics). This cuts down on cost and you can print a small file to cut down on time. I usually make 4x5 "contact" prints(from scanned 4x5 negatives). Use the Epson Standard Printer in the Space box in the Print Dialog, unless you have a good reason to use another ICC Profile. Scan and save the photograph and make other files from it(say RGB or CMYK) and save them in the same folder. This helps with shortening time, because you don't have to recreate new files. Run a grayscale(created in Photoshop using the Gradient Tool) attached to the bottom or top of the image(or run a separate grayscale in different Modes).Always check your grayscale and color preferences. I use Adobe RGB, but there may be reasons to use other RGB Spaces(see Blatner & Fraser,Real World Photoshop 5). I also use the standard built-in SWOP coated UCR for my default CMYK preferences. Whichever one you use, be consistent, even if it is a self-constructed ICC Profile. You're going to end up tweaking everything anyway in the more complicated workflows.

Grayscale Workflow

This is the simplest and most common of the many workflows available to us. It produces very fine results most of the time with the Quadtones on coated stock. It suffers from lack of control in sending the inks correctly to each Channel(grayscale doesn't have Channel Mixer), but there is some tweaking available in the Print Dialog Box(Grayscale, Gamma 2.2, Gamma 1.8 and Generic Gray Profile options in Space box)and in the Variations Command(Image/Adjust/Variations).

I usually run a grayscale test that looks something like this:

1. Scan Grayscale and edit; Unsharp Mask Last.
2. Print the Grayscale file through the Color(not Black) to get all the Quadtones working. Do 4 prints, each through Grayscale, Gamma 2.2, Gamma 1.8 and Generic Gray Profile options to see which one works best for you. Then use Variations to correct the image further. Using Variations is similar to using Levels and/or Curves. If the saturation of the ink is still too much, reduce it in the Advanced Print Dialog with the Saturation slider.

RGB

Printing an RGB file of a B&W image is still many photographers' favorite method of printing Quadtones because the Epson driver is set up to print this way. Firstly, you have to decide whether to scan RGB or scan Grayscale and then convert to RGB. You will have to do both to convince yourself which one is best for you. I then use an Adjustment Layer with Curves to reduce the amount of Black(move the Black Point straight up about 10%) in each color. If you don't do this, you'll end up with too much ink laydown, and this will bleed on coated watercolor papers.

Another method of using RGB is to Profile the Scanner, Monitor and Printer with Monaco EZColor using Epson Color inks, and then switching inks to the Quadtones to print. Monaco EZColor profiles a grayscale along with the color inks IT8 test target, and the Quadtones(the MIS Quadtones) seem to have a similar curve relationship. Monaco suggests using Adobe RGB as the RGB color preference. Variations or Curves may be used to further correct the image.

CMYK

The CMYK Quadtone workflows are the most complicated and the most controversial. They are also the most controllable in terms of ink laydown. They are for those who want the last once of quality out of their B&W Quadtone work.

The first of these workflows involves converting a grayscale file into CMYK and then tweaking each channel to control the ink and highlight dots. You can either do a mode change from Grayscale to CMYK using the SWOP coated preferences or you can do a mode change from Grayscale to Multichannel, duplicate the Grayscale channel 3 times and then doing another mode change to CMYK.

After making the change to CMYK, open the Channel Mixer using an Adjustment Layer. The object here is to change the file so that it will tell the printer to lay down a certain amount of ink, without causing bleeding or gross dot problems in the high values. Start with the settings in the following table:

The second CMYK workflow involves making your own CMYK curves and then creating an Action out of them in Photoshop to apply to a scanned Grayscale file. Creating these curves is a matter of trial, error and experience. It could be as simple as borrowing a set of known curves from someone. A complete knowledge of how Photoshop Curves work is necessary for success as well as the understanding that black ink must be removed and highlight dot contained. When you finish creating these curves the Cyan Channel looks almost nonexistent, the Magenta Channel is slightly darker than middle gray, the Yellow channel is slightly lighter than middle gray and the Black Channel exists as only about 10% of the deepest shadow areas. These are guidelines, of course.

The third, and most difficult, CMYK workflow involves making curves and, using Levels, Curves and the Channel Mixer to modify the file in such a way as to correlate the Channels to each of the 4 Quadtones in the printer. In other words, this workflow arranges it so that the highlights print with the 25% ink, the midtones with the 50% ink, the deep shadows with the 75% ink and the blacks with 100% ink. This workflow is the invention of Dan Culbertson. His workflow is covered in detail on the Digital Darkroom Singapore web site(lioncity.s-one.net.sg/~printer/bw.htm).

Scanning

I have been deluged with questions about scanning. Most frequently, how much resolution should you scan for? The best answer to this comes from the Epson web site:

"You should set the MINIMUM scan resolution at 1/3rd of the desired print resolution. For example, for a print resolution of 720dpi, you will need to set the scan resolution to 240dpi or higher. If you are going to increase the size of the printed image then you should scan at a higher dpi resolution."

The operation you should not perform is resembling in the Image Size dialog box. You can scan at a higher optical resolution(say 800)at 100%(same size) and change the picture dimensions in the image dialog box to the size you want to output, but uncheck the resample box.