View Full Version : Does a Color of the light source effects printing?

22-Feb-2007, 10:31
I just finished some contact printing last night. Because I moved across country and all my gear is at old place right now, I play with Ilford FB Mutligrade Glossy paper. To avoid short term exposures I bought a 7.5W white satin bulb, I believe for night lamps.
Exposure times range around 15-25 sec.

I think that temperature of the lamp would be in a range on 3200-3700K. My pictures turned out to be muddy, clearly, I just cannot make wites shine like whites. Oh, I forgot to mention. I do stretch the paper to avoid curling and therefore darkening effect.

So question is on the table. Should I go for enlarging bulbs? or some other types of light? How do I lower the wattage that I can make some contact and have control over it (I do not have ND filters with me)?


22-Feb-2007, 10:49
From memory enlarger bulbs tend to be 2700K not a big difference from normal room bulbs.

If you've got a couple of lighting gels. One green one blue. You could try spilt filter printing.

John Curran
22-Feb-2007, 11:27
So question is on the table. Should I go for enlarging bulbs? or some other types of light? How do I lower the wattage that I can make some contact and have control over it (I do not have ND filters with me)?


You can make ND filters out of b&w film. You can control the density by adjusting the exposure of the film. I made some by shooting a white board and placing the value in differtent zones. I can then control the amount of light in contact printing by combining b&w negs of different densities.



22-Feb-2007, 11:49
That is a great idea John. Thanks. But before I have to undergo making my ND filters, do I have to? I also have multigrade filters 6x6 to contol contrast as well.

I do have a PDF document about printing of Ilford FB. According to this article from Ilford webside there is a difference in type of light you use, but there is not too much about regular light sources. Should I consider to buy Tungsteen light source as an alternative?

22-Feb-2007, 11:59
Photofloods used in condenser enlargers are typically available in 3 sizes
ph211=75watts and about 2700deg kelvin
ph212=150watts and about 2900deg kelvin
ph213=250watts and about 3000deg kelvin

As with nearly all light bulbs, the smaller the wattage, the warmer the output in degrees kelvin. Use your multigrade filters and you should get the results you're after.

John Curran
22-Feb-2007, 13:12
Hey Pete,

I experienced a similar problem to yours when I used a purple colored contrast filter (can't remember its number) through my Omega enlarger, which is what led me to make my own ND negatives. A cooler bulb (higher wattage) might help contrast (I've heard of people using flash to expose contacts), but now you're back to extremely short exposure times which brings us back to ND. I think that any other tungsten light source will have the same problem you've encountered. Hope this is of help.


22-Feb-2007, 13:37
Thanks John,
Purple contrast filter would be anything betweeen 2 and 4. All right, Should I give a try to tungsten halogen or incandescent light higher wattage bulb? What about BR30? I have 65W and 120W one. Ir should I go even higher?


Brian Ellis
22-Feb-2007, 20:51
You can increase exposure times without changing wattage by raising the height of the light (i.e. increasing the distance of the light from the paper) if that's feasible given whatever lighting set-up you're using.

Glenn Thoreson
23-Feb-2007, 16:13
One question has not been asked - are you sure your paper is good? Develop and fix a piece right out of the box, without exposure to any kind of light. If it's good, it will be paper white. If not, it will be on the gray side of white. It sounds to me like you have a fog problem rather than the light source. Many folks contact print with those little 7.5 watt bulbs and do not experience the problem you describe.

26-Feb-2007, 10:45
I checked the paper yesterday, I processed unexposed piece of paper and came out white. So paper is good.

I also bought Incandescent Halogen Light 100W from Phillips and modified my lamp to accept filters, exposed few sheets of film to make my filters.

The result is, the light color or type of light is definitely effecting printing. 7.5W white bulb is not you should be working with. Prints are way more better, I get nice whites, contrast filters are more efficient. My exposure time was around 1.5-3.5 s. There is an issue with heat. It is buckling my filters if I use it for more that 3 seconds. I need to put film filter far more that 2 inches from the bulb. Probably to 6-10 inches.

I thought you might be interested.