RA4 Colour Head Calculator

A simple calculator for determining CMY filtration values for RA4 colour printing. Upload a reference image of your negative, select your film base and paper stock, then adjust the sliders to calculate your starting filtration values.

This tool provides baseline recommendations - always make test strips to verify filtration for your specific setup, as enlarger light source, paper age, and chemistry conditions will affect results.

Reference Image

Upload an image and adjust filtration to preview the final RA4 print.

Film Type / Grade

For colour: different film bases need different filtration. For B&W: grade controls contrast.

Enlarger Type

Different enlargers use different CMY scales for multigrade filters.

Paper Stock

Select B&W paper for multigrade printing, or colour paper for RA4.

Quick Guide

  • Add Cyan: Reduce red cast
  • Add Magenta: Warmer tones, reduce green cast
  • Add Yellow: Reduce blue cast
  • Remember: These are starting values. Always make test strips!

Baseline Filtration

Film + Paper Starting Point:

0C 80M 50Y

Adjust Filtration

0
80
50
±0

Simulates exposure time/aperture adjustment

Your Filtration

0C 80M 50Y

Colour Preview: