There is no more graded RA-4 paper on the market. All paper is probably intended for digital printing anyway. This creates problems like color crossover for optical printing. However, it is still possible to make amazing prints with an enlarger in 2025.

The lack of graded paper, however, means that contrast is not a thing you can control by simply using a paper that react differently to light.

The manipulation of contrast on the image must be done chemically.

Increasing contrast chemically

Hydrogen peroxide

Using 3% $H_2O_2$. 20ml of $H_2O_2$ added to 100ml of RA4 color developer (may be too much). Apparently “10 volumes” $H_2O_2$ == 3%. Modulating the amount of $H_2O_2$ will change the amount of contrast increase.

This makes the developer 100% one shot and must not be reused. Cyan streaking may occur. Add stop bath! Acetic Acid is recommended

Bleach & Redevelop

Needs a separate Bleach and Fix.

• Bleach must be re-halogenating bleach from C-41 chemistry, working strength. Do not use Potassium Ferrocyanide. “Kodak Bleach 3”
• Fix must be a neutral fix, like in C-41 but half the strength so dilute it 1:1 after making the stock.

Lowering contrast

Using Sodium Sulfite.

Mix a solution of “working stock” of Sodium Sulfite. 10g per liter.

Test with 5ml of that stock solution per 100ml of developer as a low contrast test reference.