Week 2: Chromatics

Week 2: Chromatics

Assignment

Complete the tutorials described within the lecture topics below.

Portal

Upload the following to Week 2 Lesson:

Week	Class Dates	Topic	Assignment Summary	File Name	Points	Due Date
2	10/11/2016	Chromatics	Duotone	duotone.psd	10	10/18/2016
				duotone.pdf	5
			Tritone	tritone.psd	10
				tritone.pdf	5
			Gamut Adjusted	gamut-adjusted.psd	10
			Spot Color	spot-colot.psd	10

Student Showcase

We will take a look at any of your new work which is ready to share.
For the business card project, we will discuss the following aspects:

• Overall strength of the design
• Degree to which:
  • the file is press-ready
  • the design meets the needs of the client

The Physiology of Color

Lesson 02: The Computer

Lesson 03: Color Management

chromatics

noun. the science of color

Color Terminology

Color Models

CMYK stands for Cyan, Magenta, Yellow and Key color (which is black). CMYK is the color model used for printing presses. It is based on the chemistry of mixing translucent printing inks rather than paint. It is called subtractive because if you mix the three primary colors (cyan, magenta and yellow) together, you get black rather than white (in theory; in reality you need to added pure black ink to get real black.)
RGB stands for Red, Green, Blue. It is based on the way the light mixes on a computer screen. It is called an additive color model because if you add the three primaries (red, green and blue) together, you get pure white light.

Gamut

A gamut is a range of colors that a particular device can reproduce. For example, CMYK can produce fewer colors than can be found in the RGB color model. Any color in RGB that cannot be reproduced on a given device in CMYK is consider "out of gamut."

Hue, Chroma, and Value

• Hue (AKA color)
  Distinguishes colors by what we would typically mean by the word "color." For example, green, purple, orange.
• Saturation (AKA chroma, depth, intensity, purity)
  Distinguishes color by the richness or brightness. One one end, you have pure color; on the other, you have gray.
• Value (AKA tone, lightness, shade)
  Distinguishes color by the lightness or darkness. One one end, you have a color near white; on the other, you have that color near black.

Hue	Saturation	Value

Warm, Cool, and Neutral

• Warm
  Red, orange and yellow are warm and visually tend to jump forward into prominence in a piece of design.
• Cool
  The cooler hues — green, blue, and purple — tend to recede in a design.
• Neutral
  A neutral a pure gray or the combination of complementary colors. Complementary colors are those that sit opposite each other on the color wheel. Neutrals are more natural colors and tend to be brownish. Sometimes, neutras are described by how warm or cool they seem.

Warm	Cool	Neutral

Spot and Process Color

Process Color

Dot patterns of cyan, magenta, yellow, and black ink are overlaid to simulate the desired hues.

Spot Color

Spot color requires blending different inks into one ink resulting in the required hue. This method resembles blending paints for household use.

Building Color with Spot Colors

You can create the illusion of many different colors using only two colors of ink printed as various screen values and overlapping each other. Using two colors in a print run is less expensive than using four colors as in process color.
The most common combination is black plus one other color. This is often referred to as a duotone.
Duotone

original RGB image

Rubine Red plate

black plate

duotone with black and Rubine Red

Activity: Create a Duotone in Photoshop

Let's try creating an attractive duotone image in Photoshop which rivals the appeal of a full-color image.

1. Locate a full-color, high-resolution photograph online or from your own image files.
2. Open the image in Photoshop and save it in Photoshop format as duotone.psd.
   
3. Image > Mode > Grayscale (discard the color information)
   
4. Image > Mode > Duotone...
5. Type: Duotone
6. Click on the large white square for Ink 2.
7. Select a Pantone color and view the preview in the main image window.
   
8. Click on the Duotone Curve square (white square with diagonal line) for each color to adjust how the color affects the overall image.
   

Sample duotone settings

6. To send the file to press, you create a PDF which has a separate image for each ink plate. Here's how:
   1. File > Print
   2. Printer: Adobe PDF
   3. Color Handling: Separations
   4. If necessary, rotate the orientation and check "Scale to Fit Media".
   5. Click Print.
   6. Save the PDF as duotone.pdf.
   7. Open up the PDF when it is done and view the separations. They will be in the same order as your ink colors in the Duotone Options dialog box.
7. Now try a tritone for a different original image (Hint: select the tritone type from the Duotone Options dialog box.) Name the file tritone.psd.

original
grayscale
duotone based on previous settings
tritone

8. Make a PDF with separations for this file and save it as tritone.pdf.

Color Spaces

• We use color models to describe the colors of digital images. 
• Color models include RGB, CMYK, Lab, etc., and each of them uses a different way of describing colors.
• In the various color models, there are color options known as color spaces. For instance, RGB, contains sRGB, Adobe RGB, Apple RGB, etc.
• Each color space has a limited range of reproducible colors, known as gamut. 
• Various electronic devices work within their own limited color gamut. Not one of them can reproduce the total range of colors seen by the human eye.
• When using Photoshop (or other image-producing software), image color values are actually being adjusting numerically.
• These numerical values have a very localized color meaning in the color space (gamut) of the device that is reproducing the color.
• Whenever your image is moved from one device space to another device with a different color space (i.e., scanner -> monitor -> printer), which can only reproduce colors in its gamut, the image colors will change.
• For example, pretty blue on screen may end up as dark purple in print.
• The color change happens because each device has mathematically interpreted the RGB or CMYK values according to its own color space (gamut).
• Because each device has a different color space, it’s impossible for all the colors you see on your monitor (RGB color space) to match the output from your desktop printer (CMYK color space).
• While color monitors are only capable of displaying certain parts of the visible color spectrum, color dye pigments used in the printing process are capable of reproducing even fewer of those colors.
• Some of the colors produced by inks cannot be displayed on a monitor, and some colors displayed on a monitor are not reproducible using inks on paper.
• Different monitors can display the same image very differently.

Adjusting the Color Space in Photoshop

Even though it’s impossible to match all colors on all devices, using a color management system is one good way to help achieve something close to consistent and predictable color between devices.  Luckily Photoshop has a very good color management system built into it.
Changing Your Photoshop Work Space Color Settings

Gamut Warning

Photoshop automatically brings all colors into gamut when you convert an RGB image to CMYK. Some detail in the image may be lost when this happens, depending on your conversion options.
You can identify the out-of-gamut colors in an image and correct them manually before converting to CMYK. You can use the Gamut Warning command to highlight out-of-gamut colors (View > Gamut Warning).

original image

viewing Gamut Warning in Photoshop
Here's how to make a manual adjustment to the out-of-gamut colors so that you have control rather than leave it "in the hands" of Photoshop:

1. Find a high-resolution image with a wide range of colors. Open it in Photoshop as save it as gamut-adjusted.psd.
2. Turn on the Gamut Warning (View > Gamut Warning).
3. Take note of the hues in your image that are out of gamut. In the image above, they are mainly yellows, reds, and greens.
4. At the bottom of the Layers panel (Window > Layers), click on the Create new fill or adjustment layer icon and select Hue/Saturation.
5. In the Adjustments panel that appears, look for the dropdown that says Master. From this dropdown, select one of the color ranges that is out of gamut. I will start with the yellows.
6. The eyedropper tools appear in the Adjustments panel.

7. Select the Add to sample eyedropper (the one with the plus sign.) Click and drag over the problem areas for your chosen color range. Note how the color range at the bottom of window adjusts as you add more colors to the color range for adjustment. Be sure to stay on the gamut warning color, you do not want to desaturate other colors in the image.
8. Once you are have the problem colors selected, drag the Saturation slider to the left, a little at a time, to bring the color into gamut.  Watch the gamut warning color closely as it disappears. Use the smallest possible slider value. You do not want to over-desaturate the colors.

9. Repeat steps 6-8 for the other color ranges which are out-of-gamut.
10. Save your adjusted file.

Below, I have fixed the reds and greens as well.

Roll over the image below to see before-and-after:

Creating Spot-Color Images in Photoshop

We already looked at desaturating a full-color image and creating a duotone. Here's how to have greater control over where spot colors are placed. This technique works best with simple graphics like line art.

1. Find a high-resolution line-art image in Google Images (hint: when you see your search results, select Large and Line Art from the left-hand options menu.) Select something with enclosed spaces that can be filled with color, and keep it simple.
2. Open the file in Photoshop and save it as spot- color.psd.

3. Image > Mode > Grayscale
4. Open the Channels panel, where you will see a single Gray channel.
5. From the panel's menu (upper-right corner), select New Spot Channel...
6. Click on the color swatch to select a color.
7. In the Select Spot Color color picker, click on the Color Libraries button.
8. Select a Pantone color (remember what number it was!) and click okay.
9. Name the spot color channel according to the color you chose (e.g. Pantone 186 C).
10. Set your foreground color to black.
11. Select the Gray channel.
12. Using the Magic Wand tool, click in an enclosed area of the image.
13. Hold the Shift key down and click in each of the remaining enclosed areas.
14. Select > Modify > Expand...
15. Expand By: 2 Pixels, click OK.

16. Select the Pantone channel.
17. Alt+Backspace to fill the selection with black. It will appear in the image thumbnail in the Channels panel as black, but as your selected Pantone color in the image window.

18. Ctrl+D to deselect.
19. You may need to zoom in see tiny details that were missed. Just paint daubs of black with a small, 100% hardness paintbrush on the Pantone channel.

When you are done, you will have two channels, each of which can be printed as a separate plate. One would be a black plate and the other plate would be printed with the color ink of your choosing.

You can turn off the visibility of the Gray channel to see how the colored plate would look on its own.

To change the ink color, simply double-click on the image thumbnail for the Pantone channel. Then click on the color swatch to change the Pantone color and click OK. The channel name should automatically change to reflect the new color.