How to successfully work in photoshop without having any colour mode incidents:
Opening a new document with default settings and selecting the greenest possible green (max amount on RGB=255)
Here is a box of greenness. Very bright and vibrant.
Though of course for printing we would want to change it to CMYK mode:
Though once changing it the green becomes much duller, as through printing in CMYK mode it is impossible to attain such a level of greenness, which is a great shame.
Therefore it is important to know how to treat an image so that the printer doesn't print colours that are not the colours that we want. Photos taken on digital cameras are automatically in RGB mode, so if they were printed straight away, the colours would not be correct. It would look slightly WRONG.
There are several ways to correct and image so that it prints the way it looks on the screen. In other words, we are synchronising the two colour modes.
A good way to establish the areas of colour that will not print as desired is to switch on the Gamut Warning as shown below:
This highlights the colours in grey that will not print correctly, as CMYK printing mode cannot print this.
Keeping the Gamut Warn on, we can then go and reduce the saturation in the image until the grey areas have disappeared, making it ready to be printed in CMYK:
A second way of altering the colour to be correct for CMYK is to use the Replace Colour Tool, where you can select certain areas to alter the hue/saturation, as opposed to messing around with the image as a whole. This would generally be a more accurate method.
A third way to do it, which is the most convenient and perhaps most efficient is to use the Proof Colours tool ,which automatically edits the image to be coloured in such a way that it can be printed using CMYK.
The slight difference can be seen in these two images below. The top one is slightly more vibrant, but would be impossible to print as it appears. The lower image loses some vibrance but is ready for printing, with no errors in colour.
Creating Swatches:
Delete existing swatches so it is possible to create a fresh batch.
Using the colour picker, is is possible to identify which colours can be reproduced using CMYK by looking at the New/Current box in the middle; there is a small box with a warning sign just to the right of that to indicate that the colour can not be reproduced.
By clicking the box, photoshop wil; present you with a slightly different colour that can be reproduced using CMYK.
This can then be saved to the swatches.
It is also possible to use colour libraries to use spot colours that are identifiable to Printers.
Remember to save these as their reference numbers, otherwise you will not be able to distinguish whether the colour swatch can be reproduced using CMYK.
USING SPOT COLOURS WITH GRAYSCALE IMAGES:
Using the same image again but grayscale. This means that it would be printed simply using black ink, and tints of this.
However we can change the colour mode to Duotone to add spot colours.
Clicking duotone will bring up a duotone options box:
We can then change the colour of the greyscale to a spot colour, as shown below. The image would then be printed, for example, simply using blue ink, and nothing else.
The curves of this spot colour can be altered to select which areas of the image will be coloured.
We can then add in a second spot colour to create a proper duotone image:
Once again, using the curves, we can decide which colours will affect which areas; in this case, I have applied the blue to the darker areas and the yellow to the lighter areas:
and there we have it, a duotone image , with the dark areas coloured in blue and light areas coloured in yellow. Magic. This can then be printed only using two colour plates, which on a large scale production operation would result in saving money, as it would be using half the amount of ink as a CMYK print. Using swatches from colour libraries would ensure that the correct colours will be printed.
APPLYING SPOT COLOURS USING CHANNELS.
We can apply spot colours to particular areas of an image using channels. By selecting an area using the polygonal lasso tool we can single out the boat:
The we can use this area as a channel in itself, by selecting New Spot Channel from the drop-down menu.
We can then select a spot colour for this area, either using the colour picker of the colour libraries.
We can then select this channel at any time to change the colour of that particular area.
By hiding the grayscale image, we can view the area singled out:
And finally, when this channel is selected, we can use the paint tools to edit the image further, to make it more detailed and perfected.
And there we have it, a grayscale image with a pink boat.
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