The secret of black, how to use it to print beautiful, pleasing

July 1, 2019

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How-to · Graphic Design · Printing

The Secret to Perfect Black
How to Get the Best Print Results

Many designers have encountered black that prints incorrectly — not a true black, or with other color tones mixed in. This problem is easily solved if you know the correct CMYK settings.

CMYK Photoshop Illustrator Printing Black Color

Why Black Prints Incorrectly

The problem of black not printing solidly occurs when designers look at the color on screen instead of checking the CMYK numerical values. On screen, all black values look the same, but when the printer applies ink according to the actual C:M:Y:K ratios, the results are entirely different.

Don't trust your eyes! In CMYK mode on screen, all black values look the same. Only check color values with the Color Picker. Incorrect values will only be clearly visible when actually printed.

Reason 01

Designing in RGB Mode

RGB mode is not a color system for printing. When converted to CMYK, colors will automatically shift.

Reason 02

Using Rich Black

Values of C100 M100 Y100 K100 cause the ink to layer too thickly, often leading to smudging issues in print.

Reason 03

Incorrect RGB Black

R0 G0 B0 when converted to CMYK results in an incomplete black.

Reason 04

Not checking Color Picker

Seeing black on screen but not checking the numerical values — leading to prints that don't match specifications.

RGB vs CMYK graphic design color systems

RGB (light) and CMYK (ink) color systems are completely different — choosing the wrong one instantly causes color shifts.

RGB vs CMYK: What's the Difference?

RGB (Red Green Blue) is used for designs displayed on screens — websites, social media, apps. This color system works with light; when fully mixed, it produces white. CMYK (Cyan Magenta Yellow Black) is used for all types of printing. This system works with ink; when mixed, it absorbs light and creates darker colors.

RGB vs CMYK — When to use which system

Color System	Used for	Principle	Suitable for
RGB	Digital media, screens	Mixing light	Web · Social Media · Apps
CMYK	All types of print	Mixing ink	Signs · Flyers · Stickers
RGB → CMYK	Convert before printing	—	Colors may shift, need checking

* Setting to CMYK from the start is best — don't design in RGB and then convert.

Example of color shifting when converting from RGB to CMYK

Example of color changes when converting from RGB → CMYK — colors that look good on screen may appear dull when printed.

Example of several CMYK black values that look similar on screen but print differently

Many black color values look similar on screen, but when printed, the results are distinctly different.

2 Correct Black Color Formulas

Octopus recommends 2 black color formulas for printing based on the area size — choose the correct type for the best results.

Type 1 — Small Areas

Text, Thin Lines, Details

Prevents ink smudging, sharp edges. Ideal for small text and thin lines.

C: 0%
M: 0%
Y: 0%
K: 100%

Type 2 — Large Areas

Logos, Large Text, Black Backgrounds

A small amount of Cyan makes the black deeper and richer. Ideal for large areas.

C: 30%
M: 0%
Y: 0%
K: 100%

Set CMYK in Photoshop

Set CMYK in Illustrator

Tips: Do not use C100 M100 Y100 K100 — the ink will be too thick, printers cannot handle it, and prints often experience smudging issues.

Before sending files, always check color values with the Color Picker in Photoshop / Illustrator.

K100 only

Black for small areas C:0 M:0 Y:0 K:100 Text, lines, small details

Rich Black

Black for large areas C:30 M:0 Y:0 K:100 Logos, backgrounds, large text

❌ Do not use

Incorrect Rich Black C:100 M:100 Y:100 K:100 Ink too thick, smudges, not recommended

Black Color Value Comparison Table

CMYK Black Values — Comparing Print Results

CMYK Value	On-screen Result	Actual Print Result	Suitable for	Recommended?
C0 M0 Y0 K100	Black	Solid black, sharp	Text, thin lines	Recommended
C30 M0 Y0 K100	Black	Deep, very solid black	Logos, backgrounds	Recommended
C75 M68 Y67 K90	Black	Brownish tone	—	Avoid
C100 M100 Y100 K100	Black	Ink too thick, smudges	—	Do Not Use
R0 G0 B0 (RGB)	Black	Shifts when converted to CMYK	Digital media only	Not for printing

* Always check color values with the Color Picker in Photoshop / Illustrator before sending files.

Pre-Print File Checklist

✓ 01

Set CMYK color mode from the start

Document Setup → Color Mode → CMYK before starting design. Don't wait to convert later.

✓ 02

Check color values with Color Picker

Don't trust your eyes — use the Color Picker to check C M Y K numerical values every time before using black.

✓ 03

Choose the correct formula for the area size

K100 for small areas · C30 K100 for large areas — don't use the same formula for everything.

✓ 04

Submit PDF file with 3mm bleed

Export as PDF/X-1a or PDF/X-4 · CMYK · 300 dpi · 3mm bleed on all sides.

Correct black — CMYK settings are right

Color shift — Incorrect mode settings

Pro Tip: If you need to design a single file for both print and online use — design in CMYK first, then export a copy as RGB for online. This is better than converting back and forth.

FAQ — Frequently Asked Questions

1Can I design in RGB and then convert to CMYK before sending?

Yes, but colors will always shift, especially bright colors and black. It's recommended to set CMYK from the beginning to avoid rework.

2Why do Photoshop and Illustrator show different black values?

Illustrator uses K:100 by default, but Photoshop often uses Rich Black automatically. Always check values with the Color Picker in both programs before sending.

3How can I fix black printing with a brownish or grayish tone?

Check if C M Y values are not 0%. If they are, reset them to C:0 M:0 Y:0 K:100 (for small areas) or C:30 M:0 Y:0 K:100 (for large areas).

4What do I need to prepare when sending print files to Octopus?

Send PDF / AI / PSD in CMYK mode · 300 dpi resolution · 3mm bleed · all fonts outlined. Our team checks your artwork for free before every print job.