Selective Colour Correction with SilverFast

SilverFast has a tool that allows you to correct - or change - a specific color in an image. This Selective Colour Correction tool is available in all versions of SilverFast, just as the Global Color Correction tool.

SilverFast has another colour correction tool that's great for photographs, the Selective Colour Correction tool. This tool was developed for high-end scanners, but it works splendidly well with an Epson Perfection 8740 or V700 as well. It enables you to change a colour within a colour. This means you can actually decontaminate colours.

In the test image, we could correct for the puppet. The puppet is not bright enough, and we could make the puppet's brownish complexion brighter. However, this would entail masking the puppet area, because without a mask, the colour correction gets applied to all red colours. I haven't used Selective Colour Correction with my test photograph, but here's what you would do, if you were to go for the Platinum technique of all correction methods: first, open the Selective Colour Correction command by clicking the icon in the Toolbar:

The Selective Colour Correction dialogue will open. With the Selective Colour Correction dialogue you will get the choice between 6 colour mode or 12 colour mode, up to 4 independent layers that can each hold their own masks, an automated, semi-automated, and manual correction mode.

An expanded view shows you all the available controls in the dialogue window. This includes the 12 sectors used by this tool. SilverFast's Selective Colour Correction indeed is a sector-based system with opposite colours on the colour wheel representing opportunities to add or subtract colours from specific other colours you define.

Changing colours in an image using a matrix of colour values

When you opened the Selective Colour Correction tool, you will have noticed an eyedropper became available. That is to allow you to select the contaminated colour area in the photograph more easily, because it can prove to be difficult to recognize blue from cyan and red from magenta.

The eyedropper tool helps with the selection. Although I won't go into detail, the Selective Colour Correction tool works by adding and subtracting colours into others. When I opened the dialogue window to correct the test photograph, I clicked on the puppet with the eydropper. The Selective Colour Correction tool selected red as the primary colour which I could now add or subtract other colours to and from.

You can do this by entering numbers in the matrix, either with a plus or minus in front of them. The primary colours are shown across the top of the matrix. The colours that you add or subtract to from the primary colour are the ones on the left. The colour bar on the right can be turned on by clicking on it. When you do, you can change all colours simultaneously.

The latter is only possible when processing colours using the colour wheel. In the centre of the wheel is your primary colour. You can add to the colour by dragging from the centre to one of the colour dots in the edge. If I wanted to add red to the red of the puppet, I would drag from the centre to the red dot.

Clicking or entering numbers

Much like the Global Correction dialogue, here as well you can select different colours to be processed at once, by shift-clicking the yellow dots below the matrix. Dots that are green, are active. Why didn't I use this tool on the test image? Well, experimenting with the tool revealed that I would get acceptable results only when masking large areas from the photograph.

This is fine by itself, of course, but when you need to mask, my personal preference goes to doing it in Photoshop, simply because the interface is less crowded there. In the test image, too many areas contain large quantities of red -exactly the colour I'm trying to boost- not to mess up the photograph rather than further correcting it. For example, the flesh tones all contain a considerable amount of red.

Boosting the reds makes the people look more like Indians on the war path than Caucasians. Nevertheless, this tool can be quite powerful, even when you want to replace a colour by some other colour. For now, we'll leave SilverFast to scan the image as we corrected it earlier.

After scanning your photograph, and finding it couldn't be corrected in SilverFast after all, you can start using Photoshop. You could also just favour Photoshop for colour correcting photographs.

(Source: IT-Enquirer)