design practice: Design For Print Workshop 2

Today we were looking at Photoshop. Specifically working with CMYK inside Photoshop correctly and the potential clashes that happen between CMYK and RGB in Photoshop, a native RGB piece of software.

Also looked at Process colours/Spot colours/Overprinting and using channels to make selections and to define and reference spot colours that can be used throughout software, not just Photoshop.

You can also get info on the colour mode when looking at the top of your picture.

RGB is a light process where red, green and blue light are mixed. The three colours combine to make white, rather than CMYK which combines to make a muddy brown/black.

RGB is an additive process

Print = CMYK

GAMUT

Gamut means RANGE. When a colour is out of Gamut, it is out of range. It won't be able to be printed.

When working in CMYK mode, some filters aren't available in CMYK, they are greyed out.

Photoshop's default mode is RGB all calculations are done in RGB, so it can be a bit tough and you need to know what you're doing to be print ready and to have consistent colours throughout your workflow, especially if you're moving between Photoshop, Illustrator etc.

^^ Gamut warning, greyed out areas are colours which can't be emulated in CMYK print processes, as it's just out of the colour gamut, CMYK isn't quite as vivid as RGB is.

How do we get around this?

Make adjustments.

You can make adjustments through Image>Adjustments but a better way is probably through adjustment layers as these are reversible and you won't lose your original document.

As you can see on the photo, some parts of the photo are still within gamut such as the lake and the trees but mainly the sky and the grass is out of gamut. So I can still keep the water intact and just adjust the sky and the grass, through adjustment layers

The above photo has had it's saturation altered this is probably the most useful adjustment to make to fix RGB gamut for printing as print process colours aren't as vivid or saturated so this is the logical adjustment to make.

PROOF MODE

Proof mode is also another mode that is very helpful for preparing for print. It's kind of like the best of both worlds, it shows how the document will look printed in CMYK in real time, so any manipulations you make won't be as noticeable as they would be without as they'll be held back to still be printable in CMYK.

It allows you to really push the saturation and colours to the limit.

Using Colours in Photoshop

You can change the swatch list to 'small list view' just like in Illustrator

But it doesn't tell you useful information about the make up and CMYK mixtures of the colours like in Photoshop and Indesign

Press ALT+ Click to delete them with the scissors tool

Once you've deleted them, you can save yourself time and delete an empty swatch. Then open a swatch by clicking on REPLACE SWATCH and opening it up. You need at least one colour in the palette though to save it as a swatch file

APPLYING COLOUR

Foreground and background colour determine what colour you work with., you can change the RGB values through the colour mixer but you can change this to a CMYK colour easily.

Spot colours

Spot colours can easily be accessed in Photoshop through the colour picker window. Just click on 'colour libraries'. Another thing I've noticed is you can pick any colour you want, and as soon as you click colour libraries, it pulls up a pretty similar spot colour from various colour systems to help you on your way.

... this triangle icon means this colour is unprintable. it's out of CMYK's gamut. you can easily fix this by moving the picker slightly till the warning signs go

The isometric cube icon below means this isn't a web safe colour so this needs to be considered too.

Once I've picked a colour it's really easy to add this to my swatch panel.

Thing with this method is, Photoshop does not store the Pantone reference within the artwork and the swatch - creating problems potentially for when sending it to print.

When speaking to the printers you'd have had a discussion about what colour system to use depending on the stock. coated or uncoated. Other colour systems such as TOYO, HKS and TRUMATCH

USING SPOT COLOURS FOR MONOTONE

The idea for using a spot colour for monotone printing is for example you might want a one-colour green print, this would require you to print with a cyan and yellow plate. Much easier and cheaper method might be to have a spot colour that's just green along with tints.

Also be looking at overprinting, which is essentially, I think, printing in layers, and in specific areas

The image has to first be in greyscale mode.

IMAGE > MODE > DUOTONE

This is me applying a Pantone Rubine Red U spot colour. The diagonal line on the left is the curve

The gradient at the bottom represents the blacks, whites and mid tones and you adjust the spot colour leveltint, for example if i want no spot colour in the mid tones I can turn it off

Duotone with two Pantone Spot colours. You can see at the top I've adjust the yellow spot colour's curve, so it has no coverage for the blacks, it just deals with the mid tones and works with the red spot colour which has the black tones.

The gradient at the bottom of the duotone options gives a glimpse of the way the coloures will be applied with the orange coming into play in the midtone area. Here's how it looks will no curve adjustment.

You can see above the red and yellow mix in all tones, dark, light and mid to produce yellow. Again

The advantage here is it saves the references and so when you save it as .tif or a .psd file the references will still remain and the printer can easily see that they're spot colours and make plates.

YOU MUST SAVE AS A PSD FILE TO MAINTAIN SPOT COLOUR REFERENCING

Considerations:

Spot colours can make prints cheaper as they are ready mixed and require one plate instead of two but you still need to consider what other colours you're using. For example if you're printing quadtone images, 4 spot colours along with process CMYK colours you could have like 8 plates including producing 4 spot colour plates which won't be cheap and might just make it more expensive for you when you could have done with 4 process colour CMYK plates.

APPLYING A SPOT COLOUR TO A SELECTED PART OF AN IMAGE

Another way to make selections in Photoshop is through CHANNELS

Channels are always black and white, the darker areas mean more colour is applied.

Greyscale images only have a grey channel...

Whereas CMYK images have...

Channels store info on selections!

You can reference spot colours in channels called ALPHA CHANNELS.

You can see here I made a selection, and clicked on

which is "save selection as channel"

You can see here the selections creates a mask. Similar to an adjustment layer, the white areas are the selection and the black acts as a mask and you can play around with this with the brush tool to paint areas black or white to mask certain areas.

Creating NEW SPOT COLOUR CHANNELS

Layer options>New Spot Channel

You end up with a white channel, where it's Similar to an adjustment layer, the white areas are the selection and the black acts as a mask and you can play around with this with the brush tool to paint areas black or white to mask certain areas.

When using the brush tool to make a selection, it gives you an overprint preview. with the ink applied how it would look when applied with transparent ink.