Nordlicht
Hello and best wishes for 2007!
A question about artificial daylight sources.
I work with black-and-white paper negatives and, above all, with liquid emulsion (fixed gradation) IN the camera.
I’m now looking for a light source that doesn’t waste as much light output – and therefore time – as warm tungsten light does. In the FOTOIMPEX catalogue, I found the Adolight 1600L/5000K and 4500/6400K.
I can’t find out much about the speed of the emulsions (so far SE1, would like to try Adolux Liquide soon). As far as I know, the monochrome emulsions are definitely sensitive to blue (6000K+), but for my application, many smaller light sources are more suitable. My question is now whether the 5000K bulbs are also suitable? (apart from the power)
I’d be grateful for any help in making a decision!
Christoph
max
Hi Christoph,
I don’t think any of this looks very promising. The only other thing I can think of apart from a flash would be HMI/HTI lights (they’re expensive for film sets, or not exactly cheap as decorative lighting for shops). However, I’ve no idea how that would work with the paper’s spectral sensitivity. I suppose it’s a case of ‘the proof is in the pudding’.
If it’s for tabletop photography, you could also try a facial tanning lamp (like the one I use as a substitute for sunlight for fine art printing). It’s limited by its light characteristics, but it’s cheap to buy. (Though safety goggles are a must.)
Regards
Martin
Nordlicht
Thanks Martin,
The HMI/HTI lights are an interesting suggestion, which I’ll look into.
Flash is obviously out of the question, as the lamps I’m looking for need to be suitable for continuous use in the studio, so I think high-output energy-saving lamps in the daylight range would be ideal. The spectral curves of paper emulsions certainly point to blue-sensitive characteristics; as a non-physicist, I would think that higher daylight temperatures also include this.
Well, after all that studying, it’s time to give it a go...
MirkoBoeddecker
The emulsion is predominantly blue-sensitive, which is why it can also be used during processing under red light.
As it is also black-and-white, you certainly don’t need expensive HMI lamps; instead, you can use standard incandescent bulbs of any wattage or our ADOLIGHT quartz halogen lamps.
As for exposure, however, a test strip would need to be produced to determine the factor between usable speed (part of the spectrum) and the exposure meter reading (full spectrum).
Daylight lamps should also work. Although they have three peaks, the blue peak at least will expose the emulsion.
It is possible that, once calibrated (to determine the factor), these are actually the most reliable light source, as the colour temperature is very consistent.
However, as ISO-P cannot be easily converted to ASA, a test exposure series is unavoidable.
Best regards,
Mirko
Nordlicht
Am I right in assuming that, in this case, I would gain usable speed by using daylight lamps rather than halogen lamps of the same light output?
Or does this only apply to colour films that are balanced for daylight using a blue filter?
If the daylight lamp were to give me about 2 stops, that would be a great achievement for me. Alongside reliability and longevity, that is the main reason why I am interested in the Adolight.
Thanks!
Christoph
