Alternate Process Exposure Light Source

[jon.oman]

I have been thinking of printing cyanotypes, van dyke brown, etc. With that in mind, I have been looking for a low cost exposure light. I ran across this set of instructions for building a DIY version:

http://www.thinktink.com/stack/volumes/voliii/equipment/uvlamp/uvlamp.htm

I'm thinking that it should fit the bill for up to 8x10 inch prints.

Note: I am not associated with the company that hosts this link. I just thought it may be interesting to others here.

Jon

[Erik Larsen]

Jon, below is a post by Sandy King about a recent experiment he did with a cheap light source. Might be something to think about.
regards
Erik


OK, you folks who already have your 1000 watt NuArc platemakers up and running
will not be interested in this relatively cheap source of UV radiation, a
Fluker's Sun Spot, a 160 Watt self ballasted mercury vapor bulb that puts out a
lot of UVA and UVB to keep those pet reptiles comfortable.
>
> I happened to try out this bulb in an effort to find a inexpensive light
source for a workshop student from Malyasia who is scheduled to be here next
week. I was looking at some of the large(440 watt) self-ballasted mercury vapor
lamps but when I looked at the SPD chart on several of these bulbs I realized
that most of them have a filter that cuts out most of the UV radiation, making
them very inefficient at printing carbon. I confirmed that fact that these bulbs
are relatively inefficient in an email exchange with a carbon printer who told
me that his exposure times with the 440 watt bulb were over an hour. This is
actually longer than my exposure times with a 175 watt street light type of
mercury vapor bulb, which has no coating.
>
> OK, I started to look around and found this Fluker's Sun Spot that is
advertised to put out a lot of UVB and decided to give it a try. I put it in a
housing this evening, sensitized a sheet of tissue, and when dry I exposed the
tissue for sixty minutes at a distance of about sixteen inches from the base of
the bulb to the printing frame to a 21 step Stouffer T45 step wedge. Guess what?
I got a maximum black at Step 3, indicating that exposure was one full stop
over, so that the tissue would have been fully exposed in thirty minutes. Folks,
that is not half bad for a $40 bulb that at sixteen inches would provide plenty
of even light for an 8X10 print, maybe even a 11X14". And the bulb is rated for
5000 hours of use.
>
> Thought this might be of some interest to some of you. So there you are,
expose your carbon prints and keep your bearded dragons, iguanas, snakes and pet
turtles nice and cozy with the same bulb.
>
> Sandy
>

[csant]

The sun is free for all ;)

[jon.oman]

Jon, below is a post by Sandy King about a recent experiment he did with a cheap light source. Might be something to think about.
regards
Erik



Erik,

Thanks for the tip. This is very affordable! I will look into this, and try it out.

Jon

[jon.oman]

The sun is free for all ;)

Yes, but it does not work at night!

Jon

[sanking]

Yes, but it does not work at night!

Jon

The UV radiation from the sun also varies a lot depending on the time of day and atmospheric conditions so it is hard to get consistent results. I would not recommend the sun as a light source for alternative printing for most of the US. However, if you happen to live in one of the arid states of the southwest or west that get a lot of sun it would be a reasonable source of UV. However, even in this case for consistency you should limit your printing sessions from about 10am - 4 pm.

Although I know of an exception or two virtually every serious alternative printer I know owns and uses an artificial light source. And given the cost of some of the chemistry, platinum for example, consistency can be a really big deal.

That said, it can be really fun to print with the sun with processes like salted paper and albumen, and very hard to beat the results since these processes really love more UV than many artificial sources can provide.

Sandy King

[Brian Ellis]

I didn't like using the sun because of all the variables involved. I have minimal handyman tools but even I was able to build a simple light box open at the long sides using plywood from Home Depot and some under-the-counter fluorescent light fixtures. There was something a little tricky about wiring the fixtures IIRC but otherwise it was simple if you have a hammer, power saw, and some nails. Then you have to get the right lights, there was some fairly big deal about them that I no longer remember but they weren't just plain old fluorescents, I think I had to order them. I'm sure Sandy or many others here know the kind of lights you'd need. I was doing mostly van dyke brown and gum printing.

[cjbroadbent]

I knocked this (http://picasaweb.google.com/lh/photo/kVSDuKuh9dYY2DfJdPZidA?feat=directlink) together in an afternoon using a 'safe' type of sterilising lamp. A POP paper under a tough negative cooks in ten minutes, my argyrotypes in 20 minutes.

[MR CORONET]

I knocked this (http://picasaweb.google.com/lh/photo/kVSDuKuh9dYY2DfJdPZidA?feat=directlink) together in an afternoon using a 'safe' type of sterilising lamp. A POP paper under a tough negative cooks in ten minutes, my argyrotypes in 20 minutes.


Chris,
It looks very nice, but I am surprised it gives even light, because I always thought of making one and belied that the lamps had to be very close to each other, with very little gap. Do you know what the bulbs are and where can in the UK could one get the Fluker's Sun Spot or equivalent please?
best of luck
Gerry

[cjbroadbent]

...Do you know what the bulbs are ...
Let you know monday pm. They are as tight as the ballast allows and seem even enough (http://picasaweb.google.com/lh/photo/9iTMXkv0xQhZMT-Mvb775Q?feat=directlink).

[cjbroadbent]

...Do you know what the bulbs are ...
The bulbs here (http://picasaweb.google.com/lh/photo/kVSDuKuh9dYY2DfJdPZidA?feat=directlink) are uvA, RADIUM RALUTEC 11W/78 G23. Look it up for an UK supplier. I got mine in Switzerland.
Here is another idea (http://picasaweb.google.com/lh/photo/iFjZpariwSzuejETbd3g7w?feat=directlink) using a tray, normal sockets and OY Airam AB 15W 6500K lamps. The time is double the uvA lamps but it gets you there with a little more heat and less money.

[Jim Graves]

Here's a really good link from an APUG discussion on this subject ... includes discussion of bulb types, ballasts, light spacing, etc.: Link (http://www.apug.org/forums/forum42/9845-question-about-uv-light-source.html)

[sanking]

Bear in mind that a bank of lights used very close to the printing frame is a diffuse light source and will not be as sharp as a point source or collimated light source. This will really be obvious in a comparison if you use a contact printing frame. For high quality results with a diffuse light source you really need a vacuum frame.

Sandy King

[Drew Wiley]

A specialty company in UV bulbs and other specialty bulbs and fixtures is Universal
Light Source in San Francisco. They can zero in on your needs pretty fast.

[Scott Davis]

You can also get blacklight fixtures at Home Depot, made by GE, for around $18-20 apiece. They are complete with BLB bulb, ballast, plug and switch. I put a bank of six of them together on the underside of an IKEA shelf, and that set will cover a 12x20 or 14x17 for sure, probably 16x20.

[jon.oman]

Bear in mind that a bank of lights used very close to the printing frame is a diffuse light source and will not be as sharp as a point source or collimated light source. This will really be obvious in a comparison if you use a contact printing frame. For high quality results with a diffuse light source you really need a vacuum frame.

Sandy King

Sandy,

You stated that the exposure time for a Fluker Sun Spot (160 watt) is about 30 minutes. Would a bank of fluorescent BLB bulbs shorten that time, and by about how much?

I don't know if you looked at the plans detailed in the original post on this thread, but they do include a method to create collimated light. Does this look like it would work out well to you? Considering that the bulbs are about 13.5 inches from the contact frame, do you think that the exposure would be significantly greater than other light sources of this type?

Thanks!

Jon

[sanking]

Sandy,

You stated that the exposure time for a Fluker Sun Spot (160 watt) is about 30 minutes. Would a bank of fluorescent BLB bulbs shorten that time, and by about how much?

I don't know if you looked at the plans detailed in the original post on this thread, but they do include a method to create collimated light. Does this look like it would work out well to you? Considering that the bulbs are about 13.5 inches from the contact frame, do you think that the exposure would be significantly greater than other light sources of this type?

Thanks!

Jon

Jon,

First, I posted the message about the Fluker self-ballaste mercury vapor bulb on the Yahoo carbon forum where most people have some experience with printing with home made carbon tissue. Bottom line is that home made tissue is generally made fairly thick and requires fairly long exposure time. So thirty minutes was for exposing home made carbon tissue, nothing else. I am fairly certain that times for many other alternative processes would be shorter, perhaps quite a bit faster.

The exposure unit described in the original message is IMO a diffuse light system, not a collimated light system. Any source that gangs up several tubes or bulbs would constitute a diffuse light system.

Sandy King

[jon.oman]

Jon,

First, I posted the message about the Fluker self-ballaste mercury vapor bulb on the Yahoo carbon forum where most people have some experience with printing with home made carbon tissue. Bottom line is that home made tissue is generally made fairly thick and requires fairly long exposure time. So thirty minutes was for exposing home made carbon tissue, nothing else. I am fairly certain that times for many other alternative processes would be shorter, perhaps quite a bit faster.

The exposure unit described in the original message is IMO a diffuse light system, not a collimated light system. Any source that gangs up several tubes or bulbs would constitute a diffuse light system.

Sandy King

Sandy,

Thanks for the clarification.

Jon