The ColorPerfect Alpha Channel Feature
ColorPerfect 1.05 has the ability to apply the accurate colors of an image to a grayscale version of the same image that has been prepared outside of ColorPerfect. The idea behind this was to be able to use the advanced facilities of Photoshop; curves, levels, masked adjustment layers, etc. to produce an image which has the perfect tonal scale (underlying B&W image) but lacks color integrity. Then, convert that image to grayscale and let ColorPerfect apply the colors to the grayscale so that color integrity is restored. Of course, once the tool is available many more creative uses will flow out of it. At the present time only the various CS versions of Photoshop support this advanced feature of ColorPerfect, but we hope that the capability may be available in Photoline in the future. This page is a very preliminary description of the feature - it is brand new to us, too - and we plan to have a better page in the near future. In particular, the example used below is not an especially good one, but it does illustrate the process.
Here we start with a color negative but we could as easily use a color positive image. First we show the negative and a result of putting the negative through ColorPerfect. It must be understood that ColorPerfect is easily capable of doing a lot more with the image, but this is the immediate result:
We then copied this ColorPerfect conversion (actually a somewhat darker version to preserve more highlight detail) to a new image and Layer→Flatten. Working with a new image is not absolutely necessary but is less confusing. Then we used selection masks, curves and levels in Photoshop to produce the following image (on the left):
As you can see, in addition to being out of color balance, this image lacks color integrity so that it cannot be brought back into color balance by any normal means. We put this image through ColorPerfect TouchUp mode and set Saturation to zero, producing the grayscale image on the right. In working on this image we avoided using pixel-moving controls like the clone brush or sharpening. The grayscale image should be a pixel-for-pixel match to the original image. Pixel-moving operations can be done later.
To be used by ColorPerfect, this grayscale image must be inserted into the Alpha Channel of the original image file; in this case the color negative image. First, using the Window→Channels panel for the grayscale image, select just the Green Channel:
then "Select All" and Copy to get all of the grayscale image. Next, click on the original image (the color negative in this case) and create a "New Channel" for the original image, using the Window→Channels panel:
So that you end up as shown in the middle. Then paste the copied grayscale image into the Alpha Channel. Activate (show colored bands) for all the channels by Shift-Clicking RGB. Generally the result will look terrible - that is normal. Then call up ColorPerfect and put it in ColorNeg mode (use ColorPos or TouchUp modes for positive images).
Most of the controls in ColorPerfect will function, but will behave differently than when working with a normal image. This is because we are using the Alpha Channel to completely specify the grayscale image underlying the color image. Thus the controls which affect only the grayscale image (Black, Highlights, Gamma, Zones,…) would be completely ineffective while controls which affect just color (CC, saturation, etc) would behave normally and controls which affect both color and the grayscale image would have only their color function. However, we decided that rather than have Black, Highlights, Gamma, and Zones be completely non-functional and useless, we would instead have them operate on the grayscale image given in the Alpha Channel, thus giving the ability to fine tune the underlying grayscale image. At present we have not altered the rest of the controls and the effects of White and BP in particular can be strange - but useful if you experiment with them. One unexpected use is in eliminating "color noise" which can crop up when using this method, particularly when working "outside the box." These controls can either increase or decrease such noise.
Returning from ColorPerfect, your image may look a lot like the one on the left below:
This is because the Alpha Channel is still active. Click RGB in the Windows→Channels box to select RGB and turn off (remove the colored band from) the Alpha Channel to get the image on the right. When you are finished working on the image the Alpha Channel can be deleted.
We believe the feature we have presented here is unique. It is very powerful and can produce both spectacular results and very innovative results. It is well worth practice and experimentation.
Go to C F Systems Home Page
Privacy Policy and E-Mail