Session includes the following:
Focus on Photoshop
Colour modes - RGB is the default Photoshop colour mode.
Spot colour within photoshop
Gamut - The range of colour which we can see on screen and how it will or will not be produced in print
Changing the colour mode within Photoshop
Colour appears and is different in different colour modes.
By turning the Gamut warning we see that the vibrancy of the colours sit outside of the CMYK range will not print, we need to adjust the brightness, contrast, levels and hues.
By adjusting just the saturation, we see the all the gamut warning disappears, however if this work is for a client and say, needs to be large scale and blown up, we need to use adjustment layers to specify areas that need to change. This isolates the are and changes only the warning in that one area.
Proof colours alters the image very subtly making it duller, the title also changes to turn on the CMYK preview, The image therefore is RGB however we see it in CMYK preview.
The swatches system in Photoshop works much in the same way as in Illustrator however deleting swatches needs to use a long process of deleting each colour individually. TO stop this process each time we open a document, we need to add just one swatch of black, and save the swatch library. We can do this by clicking "D" on the keyboard, this short cut allows us to quickly save a near blank swatch.
We can save swatches for Exchange, this allows us to open Photoshop swatches into other Adobe software such as Illustrator or Dreamweaver.
We should now create new swatches using the colour picker and inputting percentages, codes, by using the triangle and exclamation mark system we can understand if the colour we are picking is subtitle for printing. If the triangle appears, we can click on the swatch and photoshop will pick the closest matching colour.
The cube shows us if the colour is "Web Safe"
(LAB colour research)
Using libraries is the same in Photoshop as it is in Illustrator.
Please refer to Design Context for a my independent research into colour systems.
Duo tone
In Duo tone - 2 inks are used, a black (key) and a spot colour, this accents/highlights in the key which is printed.
It only works in grayscale.
The black(key) has been directly changed to a spot colour. The spot colour is directly mapped at this moment, the duotone curve tool allows us to adjust how the spot colour affects the image
The vertical Axis is the spot colour so when we adjust the curve, from say, 50% to 30%, where there was 50% spot colour, there is now 30% spot colour.
We have to save any duotone work as a .psd
Photoshop allows us to create duotones with up to 4 spot colours, so above I have used the colour picker to begin selecting C,M,Y and K to get a colour image. By adjusting the curves very slightly I have achieved a close to realistic image of the animal.
Channels
Channels of colour can be dissected to show how an image is created and printed with C, M, Y, K or created on screen with R, G and B.
Channels can store information about selections within the image, so if you have been spending time on an image and that selection is useful, we can save selections as a channel with the channel palette.
Adding the spot colour from a library can prove effective to add specific colour to particular parts of the image, however no matter what colour we chose, we must paint with black. When working with alpha channels, we over print a spot colour over the black ink, therefore we do not lose any information. We are in effect playing with transparent ink.
By applying grey (50% Key), we can produce half tones/tints in the image. This allows use to apply detail however the most useful application of spot colours, are that when we send an image or document to print, we can specify that for example "pantone 18756C" should be printed as a varnish or glue rather than printing it as that colour.
As all the channel contains is how and where the colour is applied, we can alter the actual colour using the spot colour library colour picker.
Spot colours cannot be saved as a Jpeg format due to its flattening, they must be as a Tiff or Psd. Spot colours must be checked.
Printing spot colour is not effective in lazer or ink jet printers, the only way you see the colour on the final product is in the commercial print world.
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