LCD monitor as VC light source for contact print

[salihonba]

Has anyone ever tried to use LCD monitor as a VC light source to make contact print?

Friend of mine make 8x10, and no darkroom, he used to make film scanned and viewed on monitor only, I told him he lost lots of detail on film, which scan can not capture, and advice him to make contact print, since there is no enlarger, why not use LCD as light source?

You got RGB to adjust, to change the color of light, to match the different grade of contrast needed.

Furthermore, if you need some dodging or burning in some area of the contact, you can adjust the light intensity on that area by software, to get a perfect contact in one shot, but I can foreseen that will need many further steps.

If you have these kind of experience, can you provide me the RGB value for each grade? I know that LCD differ from each other, but at least it is a start point to explore.......

[Matthew Rolfe]

I presume that you have a darkroom anyway, or you are planning to install one for making contact prints. Once you have set up a darkroom and installed all the necessary equipment to develop your prints, chemical trays etc, then you may as well go ahead and buy a cheap second hand enlarger to make contact prints from. Using an LCD monitor as a light source just seems a bit over complicated and awkward.

However, If you are up for the challenge then give it a go, good luck!

Matthew

[salihonba]

Thank you Matthew, but ironically, my friend use 8x10 in the reason to avoid installing an enlarger, or even a darkroom. He lives in H.K., a place where darkroom is a dream people can have but impossible to come true, too expensive the real estate.
Enlarger takes space, but trays are not, with large format film, and contact print only, that is the way my friend to deal with the environment around him.
So now back to the point, LCD monitor as a contact print light source is not bad if you treat if as a big flat light panel, light color can be precisely adjust through RGB value, and the light intensity also can be adjust, even you can control areas of light intensity, if you want to dodge or burn some part of image, and, these settings can be saved as a data file, for making consistent contact print, especially for those dodging and burning areas. If using VC paper,by changing color of parts area of LCD light source, split printing is feasible on contact print, but for enlarger-light-source contact print, is very tricky to get same effect.

These are the pro what we brainstormed and listed, and for the con, it will be involved with some skill of IT knowledge and image processing skill, and I think it is a way nobody (I presume?) ever tried before, not knowing how it works or not, all will be a blind-crossing-river process......

any idea or suggestion welcome, please don't leave us in dark.....

Daniel

[BetterSense]

way too complicated.

You just need some sort of controllable light source. Try a soup can with a 10W bulb in it, and a hole punched in the bottom, suspended over your negative. Heck, I used to make contact prints in my old apartment bathroom by turning the lights on and off real fast.

[salihonba]

way too complicated.

You just need some sort of controllable light source. Try a soup can with a 10W bulb in it, and a hole punched in the bottom, suspended over your negative. Heck, I used to make contact prints in my old apartment bathroom by turning the lights on and off real fast.

It sounds easy! do you control your paper grade? how to do it?

[BetterSense]

Ill ford multigrade filters. The 3x3 plain square ones are the cheapest. Or, you can come up with your own filters. I think you just need to vary the proportion of magenta and yellow light reaching the paper.

[aduncanson]

salihonba,

A knowledgeable member here has previously called attention to enlargers from this company. This contact printer uses a modulated CRT spot to dodge negatives while printing. It clearly is no solution for Hong Kong's real estate limitations, but it does prove your concept.

http://www.egoltronics.com/markv.html.

For contact printing an LCD display might work well, perhaps with suitable diffusion added. Similarly the Digital Light Projector chips commonly used in rear projection TVs would seem to serve as a modulated light source for enlarging.

Much of the same custom dodging capability is given by creating a (possibly enlarged) digital negative using a computer printer.

[salihonba]

thanks BetterSense, an elegant way to solve! I like this, and can be done immediately! for proper control the light on/off, I am thinking of a LED matrix, no heat, and can be a rectangular formation....., and no worry about on/off, always on, just block it when need it off.

[salihonba]

Thanks aduncanson, I read the link you provided, wow! it is really big! an industrial machine!
What I am thinking of the contact process need a LCD monitor and a thin piece of semi-matt glass like ground glass.

you scan your developed film in very rough resolution, say 72ppi, just for viewing on monitor, then decide paper grade and pick correspondent RGB values, and make some dodge and burn and grade change in part area, all in soft paintbrush, now this is the light source specifically for this film, it can be saved as a data file.

Now is time for contact print, stack in order 1. monitor 2.light source data file open. 3 matt glass to diffuse pixel. 4.developed film. 5. Multigrade paper.


that's the idea.


complicated? yes for first time, but think of the large format contact print, I mean really big, like 10x24 or something like that, a tailor made light source for it is worthy doing, especially for those difficult negatives.......

only in brain now.

[CatSplat]

Haha, I think the LCD lightsource is a really cool idea. Heck, you could lighten or darken areas of the screen as a form of dodging and burning if you put the screen close enough to the negative!