post alternative techniques

[SergeyT]

...I'm using a 13w spiral fluorescent bulb in a big reflector for my light source, and getting exposure times around 30:00 ...

Jay,

Could you please share more details on the bulb model, reflector , size of your prints and distance from the light source to the negative ? What %% of sesitizer do you use to get the exposure times around 30mins ?

Currently my exposures are longer then 1 hour mark and I would like to cut that...

Thank you,
SergeyT.

[Jay DeFehr]

Hello Sergey,

The reflector is 18" in diameter, and I'd estimate the bulb is about 8-9" from the printing frame during exposure. I'll get more accurate measurements and info on the bulb in a moment (I'm exposing right now). I'm using 0.1g of potassium dichromate for a 9" x 12" tissue. The tissue contains 7.5g/ Liter of pigment (aquarelle carbon black watercolor pigment), and 8.5% gelatin. More to come....

[mdm]

A very simple and fast light scource for up to 8x10 negatives is a 300W Osram Ultra-Vitalux bulb. It screws into a normal screw mount light fitting and gives very fast exposures. Mostly 7 to 9 minutes depending on film or OHP. I am using it roughly 12 to 14 inches above the contact frame. Not perfect but compact, simple, cheap and fast.

[Jay DeFehr]

A few revisions- The reflector is 20" in diameter, and the bulb is about 6" from the print frame. The bulb is a 13w FEIT Electric, BPESL15T/BLB. I paid $7 for it at my neighborhood grocery store. I hope this helps.

[Jay DeFehr]

David,

I'm sure the Osram works more quickly than my 13w bulb, but my bulb uses a hell of a lot less juice, and produces virtually no heat. I place the reflector over the printing frame, so the frame is actually inside the reflector during exposure. Thanks for the tip, all the same.

[Vaughn]

MDM -- the 300W Osram Ultra-Vitalux bulb sound interesting, but it is a 230V lamp, which may not work for many folks -- but the price is right (<$100). It does have a limited life span listed (1000 hrs).

Nice system Jay -- it helps to be able to get the lamp that close to the printing frame without heat build-up! And the price is very right!! One could even gang several together for larger image.

Here is a photo of my main set-up J(ay saw it at my workshop)...with a lamp that is no longer available...a 750W self-ballasted reflector Merc Vapor lamp.

Note the adjustable height...this particular set-up is a four-chair (12") above the printing frame and a fan is needed to keep the heat at a manageable level. I tried lower with 8x10. but got a hot spot (uneven light, not temp) in the middle of the image. I can do a three chair height with 5x7.

[mdm]

I forgot you have different electric, it should work everywhere except N & S America.

http://users.telenet.be/worldstandar...ty.htm#voltage

[Vaughn]

Here is the 11x14 negative -- just to give you the idea of the image. Photographed digitally on a light box, then inverted. Not a great job! There is some fogging at the bottom -- I will have to check out the camera and fix that.

Maple, Prairie Creek Redwoods (July 17, 2011) -- image reversed to show how it would look as a single transfer carbon.


MDM -- it should work in North America -- one just needs to have 220V wired in one's house and available in one's working area...not uncommon here. 50 or 60 cycles should not matter. But the info I read is that it will not fire up at 120V.

Vaughn

[Jay DeFehr]

Very nice, Vaughn. That's a lot of negative! I think it will be a while before I'm ready to tackle transfers larger than 8x10- I just don't have the facilities for it, but I do envy you.

[Jim Fitzgerald]

Vaughn, I know that tree! I've got an 11x14 of it also but the neg is super contrasty! I also forgot to compress my bellows so I lost some of the image. Right off of the road. I so want to go back to that spot.