Screen Printing Forum

If I have a 1-stop ND gel, does it change the intensity of light hitting my transparency film if:

a) I place the gel directly in front of my light, or
b) I instead place the gel right next vacuum frame

My guess is it makes no different in the intensity if (a) the light is filtered first then travels to the vacuum frame, or (b) the light travels first to the frame and is then filtered.

Best, David.

I wouldn't have thought that it makes a difference, but why do you want to reduce your light intensity?

I'm using a UV light and vacuum frame to make photo-polymer plates for printmaking. My exposure times are too short, under 9 seconds and difficult to control. On a recommendation, along with raising my light up a bit, I'm trying a ND filter gel to double my exposure times. Exposures of aournd 30-50 sec. would be about ideal.

Best, David

Can you just increase the exposure distance, inverse square law etc?