When should I convert images to CMYK?

This is a question we’re asked regularly and it causes some confusion. Images are generally captured using the RGB colour mode but, for printing, they need to be defined as CMYK mode. Think of it as the difference between screen viewing and printing.

Image of screen and printer icons

The initials RGB represent the primary colours of the screen mode – Red, Green and Blue, CMYK represents the primary colours of printing – Cyan, Magenta, Yellow and Black (Black being represented as K or the Key colour).

In the early days of desktop publishing, images were converted to CMYK using Photoshop before they were placed into a design application like Illustrator, QuarkXPress or InDesign. This process can be time consuming and creates a variety of inconvenient side-effects. The CMYK colour mode is adapted for specific printing processes and machinery and has a reduced colour range compared to RGB so CMYK images so are not suitable for reuse in many other media. A further benefit from leaving images as RGB is that much of Photoshop only works in RGB mode so, if you convert an image you’ll find a substantial amount of Photoshop’s editing capabilities are disabled.

The good news is, this process is no longer necessary, as long as you are exporting your  document to a PDF using a preset which includes a colour conversion.

Screenshot of Photoshop Convert to CMYK mode

 

Let’s explain that further. The typical way to change colour modes in Photoshop is to manually select Image>Mode>CMYK Color, however,  as all Adobe applications use the same colour engine, you can perform an RGB to CYMK conversion at any point in your workflow using any Adobe application. If you are sending print-ready PDF’s to your print provider, you can automate the conversion by placing RGB images into InDesign or Illustrator and creating a PDF using choosing a preset such as PDF/X-1a2001 or Press Quality. These presets contain a built-in conversion which will convert any images to CMYK automatically. The original pictures will remain untouched, leaving you free to reuse them for output in other media without making duplicates.

Screenshot of InDesign Export to PDF

SCreenshot of second step of InDesign export to PDF process

This does not automate creative processes such as colour correction, retouching or sharpening and these should be carried out in Photoshop in conjunction the various soft proofing tools such as Proof Colours and Gamut Warning.

In cases where you intend to send open InDesign files and links to your print provider this approach is not suitable (unless you’ve agreed that your print provider will perform the conversion). For most people, however,  converting on export to PDF offers a much quicker and more efficient way to ensure images are correctly adjusted for print.

To learn more about working with colour with Creative Cloud, contact us.

 

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The designer’s guide to grid theory

I spend a lot of time emphasising the importance of grids both in my commercial training as creativelab and also as a lecturer at the University of Stirling. Creativebloq has posted this useful introduction to grids in design. It;s primarily about screen design but many of the principles are true for print too. Well worth a look.

Source: The designer’s guide to grid theory | Creative Bloq

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Question of the week: why do my Jpegs appear with different colours?

It’s quite common for photographers to use multiple image editing applications for different purposes, handing image data from one to the other to access different and unique editing features. In this case a problem arose when images were handed off from Lightroom to Photoshop before being saved as a Jpeg. The Photoshop generated Jpeg had distinctly different colour appearance than those of the same file exported directly from Lightroom and Photoshop Elements. This was quite an interesting issue to troubleshoot as it took a bit of detective work using some less well known Photoshop and Lightroom tools.

Image comparison
Compare the three sample Jpegs below. In the one generated by Photoshop, the blues of the sky, water and boat hull are different to that in the files created by Lightroom and Photoshop Elements.

'Exported' from Lightroom
Jpeg ‘Exported’ from Lightroom. Image courtesy of Tom Flint
'Save As' from Elements 11
Jpeg ‘Save As’ from Photoshop Elements. Image courtesy of Tom Flint
'Save As' from Photoshop CC
Jpeg ‘Save As’ from Photoshop CC. Image courtesy of Tom Flint

This is a colour settings issue and the 3 applications are each doing something slightly different with the colour data.

Analysis

Each application has a predefined set of colour rules for creating and converting colours. Lightroom is  proprietary and cannot be user-adjusted, Photoshop and Photoshop Elements are configurable by the user. The rules are applied whenever you create a new colour, do a mode change, print a file or export to a different format. In each case, the applications are configured slightly differently so are producing slightly different results.

I made a colour sampler reference point on the boat hull of each of the images, the results are in the screenshots below:

Save as from PSE
Colour sampler from Photoshop Elements
exportfromLR
Colour sampler from Lightroom
Saveas from PSCC
Colour sampler from Photoshop CC

 

The colour data (denoted by #1 in the screenshots) is quite different in the Photoshop CC version, which has higher red and green values but lower blue values.

I then checked the colour profile of each image (using the Photoshop Document Profile setting), Lightroom is sRGB, Photoshop Elements is Adobe RGB and Photoshop CC is ProPhoto.

Each of these has a distinctly different range of colour. You can choose the colour profile that is attached to a Jpeg either on export (with both versions of Photoshop) or under the Export panel settings in Lightroom.

Lightroom defaults to converting Jpegs to sRGB on export. sRGB is quite a small colour space and the RAW data of the original image will most likely be outside its range hence, Lightroom will perform a colour conversion on saving.

Screenshot of Export settings Adobe Lightroom
Export settings Adobe Lightroom

Photoshop Elements defaults to Adobe RGB which is a much bigger colour space. Note the values here are fairly close to the Lightroom output. Photoshop Elements either maintains the existing colour profile of the image or converts to either sRGB or Adobe RGB on export, see below. Photoshop Elements normally converts RAW images into Adobe RGB when converting from the Camera RAW processor. Adobe RGB will then be used by any subsequently generated Jpeg.

SCreenshot of Photoshop Elements 'save as' settings
Photoshop Elements ‘save as’ settings

The Photoshop Jpeg is saved as ProPhoto which is the default colour space used when Lightroom hands over the image to Photoshop. This colour space is vast and maintains (more or less) the colour data present in the Lightroom/RAW original. When you save this as a Jpeg, Photoshop keeps the profile unless you decide to change it.

SCreenshot of Photoshop CC 'save as' settings
Photoshop CC ‘save as’ settings

To change the colour profile in Photoshop you can select Edit>Convert to profile and choose the appropriate profile from the list as below:

Screenshot of Convert to Profile, Photoshop CC
Convert to Profile, Photoshop CC

This can now also be automated by using Photoshop CC’s new ‘Export As’ function which is useful for batch processing export of Jpeg and PNG files.

Screenshot of Photoshop 'Export As' function
Photoshop Export As function

By setting up each application to convert image data using the same colour profile, each application creates a Jpeg with the same colour appearance and values.

Colour management can be a tricky business and I often find that people find it confusing and technical. The inexplicable colour differences in the examples here illustrate what happens when colour management settings are not set up consistently.

If you have colour issues or would like to know more about colour management please contact us at info@creative-lab.co.uk

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Creating vector shapes with Illustrator Live Shapes

The November 2015 update to Illustrator brought with it some useful but very subtle new features that are easily missed.

As you draw shapes you may notice some extra icons and smart guide activity. These are a new feature called Live Shapes. Live Shapes allows you to draw and manipulate shapes more quickly, easily and accurately without the need to constantly change tools to do so.

SCreenshot of Illustrator polygon
Illustrator polygon

In this example we drew a polygon with the standard polygon tool. On completing the shape (and without deselecting the polygon tool) the enclosing frame is now peppered with icons, each of which can adjust the shape in a specific way.

Screenshot of Live Shapes Widgets
Live Shapes Widgets

Scaling and rotation are self explanatory however it is not necessary to select the selection tool before using these widgets.

SCreenshot of Edit Corner Radius
Edit Corner Radius

To change the angle of any corner, use the drag the corner radius widgets. A blue highlight will appear to indicate the current corner, this turns red when the maximum radius is reached.

Shape centres are easily identified with the Centre point widget and this can also be used to move the shape around-again without using the selection tool. Polygon shapes also have a Side widget which allows the number of sides to be dynamically edited by dragging.

Screenshot of Edit Sides Widget
Edit Sides Widget

The shape properties can also be adjusted in more detail using the Transform panel which now features a variety of new controls.

Elliptical shapes can be further adjusted by using the new Pie Widget which divides the ellipse into sections via a simple drag motion. This can also be inverted to create individual slices.

Screenshot of Pie Widgets
Pie Widgets
Pie reverse
Pie Reverse

In addition to these features you will also notice new Smart Guide hints which appear as magenta lines as you draw and adjust shapes. New hints include trajectory indicators, diagonal hints and hint crosshairs. The Smart Guides can be controlled by using the Smart Guide Preferences pane.

Screenshot of Smart Guide Preferences
Smart Guide Preferences

The Live Shapes features are at least partly designed for use on tablet devices, specifically Microsoft’s Surface, but they add some really intuitve and useful functionality for desktop users too.

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