How do you use Extended Grays?
Posted by Larisa Bolli on 27 July 2009 02:45 PM
First, print one of the color targets (either 225 or 729 patches; I'd suggest
starting with 225, to keep things simple, then try again with 729 later if you like).

Then print the Extended Grays target. If you do the 225 colors and the 238
extended grays, you'll have two sheets of letter size targets ready to measure.

It's extremely important that you print both of these on the same paper, using the same driver settings.

Then, on the Read Patches screen, measure each one of them. Before you step forward into that screen, you need to set "which" kind of target you're going to be measuring on the Select Target screen. So: Select Target: 225; click Next; Save Measurements To...; then Read Patches. Step back to Select Target: Extended Grays; click Next; Save Measurements To...; Read Patches again. Now you have measurements saved for colors, and for grays.

Visually check them, too, for accuracy. Open up the Target window for each, switch to Measured mode so you can see only the measured colors, drag on the lower right corner to make the window even larger, then visually compare to your target print. You should see a reasonably close match. Look for "bad" measurements, which (if they exist) will typically be too-light patches that stand out among their neighbors in the darker regions; they should be easy to spot. Remeasure any bad ones (arrow keys to locate the patch, then measure again).

Now that you've got these, you can Build.

The Extended Grays are used as a supplement to the colors; but you don't build a profile straight from them; that why if you select them in the measurement list, you can't step forward to the Build screen. (We have to let them show UP in that popup, though, because you need a way to measure and preview and possibly remeasure them).

Instead, this is what you do:

- Select your COLOR measurements in the main popup on the Read Patches screen.

- Once you do this, another checkbox and popup (smaller) will show up below
that, and your Extended Grays measurements will be in THAT popup. (All
Extended Grays measurements that are in your Data:PRO folder will show up in this supplementary popup below the main popup). Use that smaller popup to select "which" extended grays measurements you want to use; and then CHECK the checkbox if you want them to actually be USED when you build the profile. (If the checkbox isn't checked, then when you build, only the color measurements will be used when you build the profile).

- To summarize: to build a profile with Extended Grays used as part of the
profiling process:

- Measure a color target and a grays target

- Select the color target in the main popup

- Select the extended grays target in the supplementary popup that appears below it; and also CHECK the "Use extended grays" checkbox.

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