Sun exposure...

[chrobry]

I did a 16x20 test today. Very weird day with the sun diffused by a lot of smog. Amazing how fast the exposure was. 5 minutes top and for sure it was over exposed.
Was it because of this huge diffused light ?

5 minutes is quite long for Southern California, I think. I expose my kallitypes which are of similar speed to VDB I guess for only about 1 minute in Tucson, AZ . It must be this smog but it had to blocked UV.

Jan

[z-man]

5 minutes is quite long for Southern California, I think. I expose my kallitypes which are of similar speed to VDB I guess for only about 1 minute in Tucson, AZ . It must be this smog but it had to blocked UV.

Jan

i believe that the ususal cloudless conditions in az allow the original point source-the sun-to over ride any other considerations-the uninterupted power of the sun in your part of the world is both a blessing and a curse i think

you dont mention where you position your frame-out in the open under the sun- or in open shade

a reading of the literature available in english from 1800 on will give a foundation to understand the variables

then we can discuss the uv blocking or passing of smog and other materials

and the variables of the response of different lite sensitve materials to various proportions of visible and uv radiation

the variables of the response to different colors of visible lite and the mixes and color temperatures

point source vs large both difuse and collimated

and so on and so on and scooby dooby doowah

sometimes i wish i lived in az tho

vaya con dios