Light sources for contact printing

[Dan Smith]

This question is directed more to those who contact print their negatives with t he resulting print being the finished piece. Large negs of 5x7 and up. I found I get a cleaner print that appears sharper when I contact print my 8x10' s using a small halogen lamp, the type purchased at Home Depot or Office Max typ e of stores. The ones using the very small 20-50 watt halogen lamps. I put it ab out 2-3 feet above the printing frame & then expose the Azo paper or regular pap er under it for the appropriate time. When some friends have looked at the resulting contacts they have picked the pri nts done under this little lamp as having better separation and apparent sharpne ss in comparison to those done under a normal 150 watt bulb and a 200 watt flood and spot. The prints look good and the system works well. Little inexpensive light that pu ts out a very clean light to print by. One I can easily carry with me when I tra vel so I can develop & print in a motel bathroom from time to time when checking that lenses, film & holders are all doing well. Anyone else try something like this & find an apparent difference? Or, as is oft en the case, am I seeing what I want to see?

[Sean Billy Bob Boy yates]

Sounds a whole lot like what Erik Ryberg brought up in this forum a long time ago. I think the conclusion was that a smaller, more "point" light source will result in sharper prints. As I recall he was saying he got sharper prints using his condensor enlarger than with a bare bulb.

[Sean Billy Bob Boy yates]

http://hv.greenspun.com/bboard/q-and-a-fetch-msg.tcl?msg_id=000NWB

[pat krentz]

I have tried several different light sources (incandecent, cold, and black light) I found that the black light plant bulbs worked the best for me. A 75w bulb in a 11 inch spun reflector at 2.5-3 feet above the paper with the time set for 2 second burst every 1/2 inch or 3 second burst for very heavy negs. on Azo grade 2. Pat

[Carl Weese]

Dan,

Have you tried filtering that little light for VC papers? I've been trying to figure a way of printing on VC paper (to take advantage of pyro-developed negatives that can also print in platinum) using my big Nuarc vacuum frame that's too big to put under an enlarger. I'll have to go to one of those chain stores and look at little halogen lamps. Maybe combined somehow with large acetate VC filters..

[Carl Weese]

Forgot to comment on the original question: carbon printer Sandy King has done careful tests and found that there is a difference between highly diffuse (UV flouro tubes) and point source (plate-burner) when exposing a contact print from a 'backwards' negative (this is done to get a right-reading single transfer) but that the sources made no visiible difference in his tests when the negative was printed in the normal way, emulsion to emulsion. Whether printing on Azo instead of carbon tissue affects the question, I don't know.

[Brian Ellis]

I've used everything from normal household bulbs to halogen bulbs to "warm" household bulbs to small flood lights. I've never seen any difference among any of them when contact printing on Azo paper (except, of course, in exposure times). I'd be very surprised if the light source makes any difference in "sharpness" with a contact print. Of course it wouldn't be the first time I've been surprised. : - )