Exposure times
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Exposure times
Hi, I'm using a 110 mesh with Ulano TZ emulsion. I have a 750 watt halogen light which can operate at 250 and 500 watts as well. Can anyone give me a rough estimate of how long I should expose for and at what distance the screen should be from the light? Thanks for your time!
Re: Exposure times
Depends on how big your screens are - larger screens require a greater distance to keep the exposure even.
Get a Stouffer step wedge and expose to a solid step 7. It is the best way I'm afraid.
Get a Stouffer step wedge and expose to a solid step 7. It is the best way I'm afraid.
Re: Exposure times
They're 20 x 24. Is there a way to do it with out the step wedge? I'm already financially more invested in this than I'd like to be. Thanks anyway Tom!
Re: Exposure times
Get a piece of card and a screen.
Cover all but 1" of the screen and expose for 1 min.
Move the card so that you are covering all but 2" & expose for 1 min.
Continue until all your screen is exposed.
Now you have a screen where 1" has had a 20 min exposure and a series of 1" strips have progressively less.
The poor man's step wedge.
You will see the 1 min wash out then some that don't wash out properly and at some point you will decide that one is good enough and that's your exposure.
Distance should be somewhere near the diagonal distance across your frame - 20 x 24" is about 31", keep an eye on this if you get differential exposure across the mesh.
Cover all but 1" of the screen and expose for 1 min.
Move the card so that you are covering all but 2" & expose for 1 min.
Continue until all your screen is exposed.
Now you have a screen where 1" has had a 20 min exposure and a series of 1" strips have progressively less.
The poor man's step wedge.
You will see the 1 min wash out then some that don't wash out properly and at some point you will decide that one is good enough and that's your exposure.
Distance should be somewhere near the diagonal distance across your frame - 20 x 24" is about 31", keep an eye on this if you get differential exposure across the mesh.