21-Step Screen Exposure Guide
Details
Stouffer's 21-Step Exposure Guide
These guides give you 21 steps of photographically shaded film from 100% total black opaque down to 100% total clear. Use these as a simple method to test for correct exposure. Once your correct exposure is determined, put one on every screen to be exposed so you can maintain your settings.
Directions:
- Place on screen alongside your positive.
- Expose at your normal time.
- If Step 7 or lower (6,5,4,3,2,1) washes out, you are UNDER-exposed
- If Step 8 or higher (9,10,11,12-21) does NOT wash out, you are OVER-exposed*
- If Step 7 does NOT wash out and Step 8 DOES wash out = perfect exposure time
- * If the upper steps(17,18,19,20,21) do NOT wash out, your screens may be pre-exposed. Be sure to dry screens in complete darkness and use our Screen Room Safe-Light fl tube sleeves.
In the picture above, Figure A is a correct exposure time. Figures B & C are both under exposed.
Use the following chart to figure out how long to increase or decrease your exposure.
For example:
- To INCREASE the number of Steps that are NOT washing out, multiply your original exposure time by 2.82 to move 3 Steps HIGHER.
- To DECREASE the number of Steps NOT washing out, multiply your original exposure time by .50 (or 50%) to move 2 Steps LOWER
To Change Exposure | 1 Step | 2 Steps | 3 Steps | 4 Steps |
Increase Exposure | 1.41x | 2.00x | 2.82x | 4.00x |
Decrease Exposure | .71 | .50 | .35 | .25 |