At the start of the session Mike told us a few essential things to know about Photoshop:
- Along the top of the image you open it will be set up as RGB or CMYK.
- To change the mode you then just have to click on image and then mode and then select the change you'd like to make.
- When you open up an image from a digital camera or something that has been scanned then it will come up as being RGB.
- The range of colour that you can produce with CMYK isn't as great as the colour you can produce with light.
- When converting a colour from RGB to CMYK photoshop changes the colour to the nearest printable colour. Much less bright and fluorescent.
- RGB files are smaller.
- All of photoshops calculations are working with RGB.
To be able to tell whether the colours are printable colours we can click on the Gamut Warning in the View menu.
The grey shows the colours which are not printable.
We can adjust the hue/saturation of the image to make it printable and remove the grey area.
You can also create an adjustment layer using the button at the bottom of the layers palette.
You can adjust the saturation and then use the paint brush tool to alternate between the black and white. The black makes a hole in the mask whereas the white indicates where you have made the adjustment to the image. This allow you to keep areas of the image as vivid as you'd like them to be, without having to affect the whole image. Adjustment layers are temporary so you can remove them at any point.
When we select proof colours, this allows us to see what it would look like when we convert it to CMYK. This is therefore just a preview of CMYK. It is important that you turn this on immediately when you start working on the image. There is no point in using it half way through editing.
The default it working CMYK which is the one most useful for us when working for a printed outcome.
From 'Adobe Photoshop' printing images to a commercial printing press.
Work in RGB mode until you finish editing your image. Then convert the image to CMYK mode and make any additional colour and tonal adjustments. Especially check the highlights and shadows of the image. Use levels, curves or hue/saturation adjustments layers to make corrections. These adjustments should be very minor.Flatten the file if necessary, then send the CMYK file to the professional printer.
To clear out your swatch palette you have to press alt and click on each swatch and they will all delete one after another. This is quite a long process though.
To add a swatch change the foreground colour and then click on the swatches panel and it will be added to the palette.
If we double click on the colour down the left hand side, it will come up with this box. The bottom colour suggests the mode suitable web safe colour.
We can then save our swatch palette. Your swatch is going to be saved for a particular project, it therefore makes sense to save this swatch in an accessible place.
We can then save our swatch palette as shown below in the image. If we reset the swatches our old ones will appear back there.
How we can work with spot colours:
If we click on the colour picker and then colour libraries we have all of the pantone swatch books to choose from. If you are preparing something which is going to use spot colours then you would ask the printers which is the most appropriate colour for the stock you are using. Use the specific book.
In this example we are using the solid uncoated. Then choose the number you need, for example 165. Click ok then you will then see that colour loaded in the foreground square. This colour is now ready to use for our image.
We can then click on the swatch panel and the colour will be added.
For a spot colour to work we need to make sure that the reference is correct. In Illustrator it would have been named properly whereas in Photoshop it is only known as swatch number 3. Another reason why it won't work it because a Photoshop image can only work with one colour mode at a time. The mode of a Photoshop image is fixed. Spot colours are not going to work as far as inks go. This image will still be printed with CMYK. We therefore need to consider inks as well as colour.
We are going to look at two techniques:
Creating a duo tone image
In this sense, tone means ink.
If we go on image, mode and then duotone it comes up with this options box.
To be more specific we can choose the library again.
This enables us to change how the new ink differs from the original black ink.
This is effectively adjusting the brightness and contrast of the new image.
Reset back to black.
There are also some preset colours which we can use as a starting point and this changes the curve as well.
The final way to work with spot colours is to work with channels.
Each channel is a greyscale image specifying different areas of light and shade. This is shown when viewing all of the different channels. This links back to printing plates. Channels specify inks, spot colours are printed with individual inks (CMYK). Somewhere in the channels palette I am able to work with CMYK as well as spot colours.
We can choose another spot colour from the menu. Then click ok.
Using the paint tool you can then colour in areas of the image.
You can change the solidity as well to change the opacity of your image. This is a very creative technique of creating digital art which is then going to be used for screen print. You can buy different inks that have different values of opacity.
Spot varnishes - For example, we would prepare our image using this technique to be able to spot varnish.