slide correction

[cozmicray]

I need some help using X2 to correct slide digital copy

Slides at link below show slide illumination (MWC79)
How can I take this and correct all my other slides
like the one in MWC72 that was illuminated with same source?

Basically slide MWC79 is image of light source and lens effects without slide in copier,
how do a subtract it out of real slides?

https://lh6.googleusercontent.com/-M26b ... ection.jpg

Tnx

[hartpaul]

I gather from that link that you are trying to duplicate some slides and from your posted image of setup without slide wondering how to use PSP to correct the illumination problem (shadows in corner hot spots and other uneven lighting) . This would be difficult and time consuming.
You would be better to get it right in the duplication process.
From memory a sheet of perlite or white perspex was the go for giving a neutral white background. Then your light source had to be strong enough and far enough away out of focus that the light was even across the surface.
To check place a thin sheet of film plastic with a black cross in the centre and focus on that and then check the light around the edges to see that there is no drop off or hot spot. You should also be able to do a custom white balance on that as well to further reduce the amount of correction you need to do.
After that it is only the exposure for each slide that you need to worry about . Underexposed give a bit more time, over exposed a bit less. If the slide is washed out then you have totally lost detail and no amount of digital correction will return that detail.

[cozmicray]

This is part illumination, part condenser in illumination, and macro lens, and lens utilized.

My slides in many 100 slide reels.
I modified a projector that uses the reels and shoot the slides as they
are loaded into the projector with a digital camera with macro lens.

I have to reverse them since they are not being projected.

While experimenting -- shooting slides off of a screen or rear projection
gave very bad center hot spot.

There has to be away to dodge or burn this illumination out.

Tnx

[hartpaul]

You could try photographing the light pattern as is and then invert the image (Light becomes dark, dark becomes light) and then apply this over yourbasic image and change the opacity ril the lighting appears even an this may be the correction you need to apply to each photographed slide.

As said though if you can change your illumination to slide distance and have a smaller depth of fiels you may put the lamp out of focus totally.
I remember duplicating slides with an attachment that was screwed onto the front of the lens with a slide hoder there. You just aimed the contraption at a neutral white surface strongly lit and photographed the slide. Had a pearlite screen and lighting was as even as the lighting on the surface you aimed it at.