Dot gain (Tone Value Increase, TVI) is the difference between the nominal dot size on the printing plate and the actual dot size printed on the substrate. A 50% plate dot that measures 70% on press has a dot gain of 20%.

What densitometer readings do I need?

You need two readings: the tone density (Dt) measured on the tinted patch at your chosen nominal percentage, and the solid density (Ds) measured on the 100% solid ink patch. Both are measured with a reflection densitometer using the same color filter.

What is the Murray-Davies equation?

The Murray-Davies equation calculates effective dot area from densitometric readings: EA = (1 − 10^(−Dt)) / (1 − 10^(−Ds)). It is the ISO standard method (ISO 12647) for tone value calculation in offset printing.

When should I use the Yule-Nielsen correction?

The Yule-Nielsen modification corrects for optical dot gain caused by light scattering within the paper. Use n = 1.7 for coated papers and n = 2.0 for uncoated. Higher n values reduce the measured effective dot area compared to standard Murray-Davies.

What dot gain is acceptable?

For GRACoL/SWOP offset printing, a dot gain below 10% is acceptable. Gains of 10–20% are moderate and may need compensation curves. Gains above 20% indicate a press or plate problem requiring attention.

Dot Gain Calculator

Name: Dot Gain Calculator
Availability: InStock
Author: Nham Vu

Enter your plate dot percentage and densitometer readings to calculate dot gain (TVI) using the Murray-Davies equation and Yule-Nielsen correction.

Densitometer Inputs

Enter plate dot % and densitometer readings

Nominal Dot % (plate value)

Dot size on the printing plate (e.g., 25, 50, 75)

Tone Density D_t

Densitometer reading on the tinted patch

Solid Density D_s

Densitometer reading on the 100% solid patch

Yule-Nielsen n-factor (optional)

1.7 = coated · 2.0 = uncoated · 1.0 = Murray-Davies only

Sample test cases

Enter values and click Calculate to see results

Copied!

Summary

Enter your plate dot percentage and densitometer readings to calculate dot gain (TVI) using the Murray-Davies equation and Yule-Nielsen correction.

How it works

Enter the nominal (plate) dot percentage — typically 25%, 50%, or 75%.
Enter the tone density (Dt) from your densitometer measured on the tinted area.
Enter the solid density (Ds) from your densitometer measured on the 100% solid ink area.
Optionally adjust the Yule-Nielsen n-factor (default 1.7 for coated, 2.0 for uncoated).
Click Calculate to see effective dot area, dot gain, and quality classification.

Use cases

Press operators calibrating ink density settings during makeready.
Prepress technicians validating plate linearity before a press run.
Print quality control teams checking conformance to GRACoL or SWOP standards.
ICC profile builders measuring TVI curves at 25%, 50%, and 75% tone values.
Flexographic printers tracking anilox and plate dot gain across substrates.

Frequently Asked Questions

Last updated: 2026-07-15 · Reviewed by Nham Vu