I'm attempting to do a shot without causing damage to my camera...A hour long exposure of a sunset. I've have used two pieces of welder's glass and got this shot. It caused a purple haze over a good portion of the image. I'm assuming it's infrared or UV light??? If this is the problem, is there a filter like a IR cutoff filter that would do the trick? Or would I need something better?
that purple haze is probably a color cast caused by the glass itself; the welders glass often isn't neutral color.
you should be looking at solar filters, or very dark (and probably stacked) ND filters. Thousand Oaks sells solar filters, to name one company.
This is just the diffused light going through the welder glass. It comes from two sources:
- the sky and
- the two welder glass. (These have coplanar surfaces that allows for bouncing the light for long.)
You cannot do anything with those either. You need to use optical quality filters (ND filters of high value) to achieve this effect, although then you will only have a trace of the Sun and most of the details might get lost.
I never tried it and would probably start with image stacking as opposed to one extra long exposure.
In any case, take a look at IRND filters that are designed to filter out the IR spectrum from some 740nm. The IR pollution causes unwanted color shifts in the images. I don't know if these filters can prevent heat damage, another reason why I would use them for series of short exposures as opposed to one extra long.
Purple is the welders glass remember welders glass is specially designed to protect our eyes not reduce light transmission as is a nd filter, and is also often seen when stacking cheap nd filters bought from ebay and the like as well.