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Thread: DIY graduated filters?

  1. #1

    DIY graduated filters?

    Hey
    after watching A Short Film about Killing (from the decalogue)
    and discovering the cinematographer made 600 hand made lenses i am dieing to work out how to do it!?

    obviously i need some good quality plain glass and something to hold these bits of glass into place! But does anyone know what i need to graduate the glass with colour? Is there just simple glass paint that i can use to layer lots of thin coats of?

    Any ideas, suggestions or answers would be great,
    I'd mostly be using the filters to reduce contrast of sky and land on landscapes and to also add tints etc!

    Cheers

  2. #2

    DIY graduated filters?

    I used to have some paint which I bought from a local art shop which was for glass. It was for creating stained glass window effects. I had green and red but it was available in a variety of colours (not sure about grey though).
    This was a translucent paint designed to let light through and if it was applied carfully with a consistant coating weight and a smooth surface, it wouldn't mess up the image much (i.e. diffuse it).

    Steve Smith

  3. #3

    DIY graduated filters?

    cool,
    did u actually use it for creating filters? If so were the results very good, i'm planning on making these filters to use on a final year Uni film that i'm planning to shoot over the summer, so obviously they need to look good!

    It sounds like a good place to start tho!

    Do you (or anyone else) know how professional filters are made?

    Thanks for your help

  4. #4

    DIY graduated filters?

    No, I didn't use it for filters. I'm not sure why I bought it now (it was 20 years ago) but I do remember mixing the red and green together to make a wood stain!

    I think professional filters are dip coated. We used to sensitize our own PCB material many years ago with a home (work) made dip coater. Basically you have a bath of liquid/goo/etc. and have a motor driven holder which first moves the sheet vertically into the mixture then pulls it out slowly at a controlled and consistant speed leaving a thin and very consistant thickness on the sheet. I think filters are coated in a similar way although I could be wrong (I was once but I don't like admitting it!).
    I would imaging that varying the speed during the process would vary the coating weight in different areas. (Our PCBs needed the same thickness all over).

    I would have a go with some glass and some coloured gloss varnish. Dip it in by hand to a half way point then pull it out slowly and evenly. Leave it to dry and you might end up with a hard edge graduated filter. Fine for monochrome. Call it a mahogany (or whatever) tint for colour.

    This method will obviously coat both sides at the same time so you may want to use some masking tape to mask one side. If you get some coloured glass paint as I suggested earlier, you can try coloured filters.

    Steve Smith.

    Steve Smith

  5. #5

    DIY graduated filters?

    I know some, perhaps many, modern coating glass coating methods involve vapor deposition. One scenario is electron beam bombardment, in a vacuum chamber, of a piece of the material to be applied. The material is vaporized, and somehow attracted to the target substrate (surface). With conductive objects, they can be charged. With dielectrics (insulators), I don't know how they control when the vapor lands. I have heard of processes in the semiconductor inductry wherein the thickness is measured as a function of mass change...the one scenario described to me was set up as a dielectric oscillator & the change in frequency was used to determine when sufficient thickness was applied.

    Sputtering is the name for at least one of the vacuum deposition of material vapor processes.

    Now, a dip process may work after a fashion for a filter, but I don't think it's precise enough for coatings on optics...and then I wonder if it's flat enough for optics...glass filter quality usually includes a flatness spec.

    To counter this...there's always the fact that things can be made to work to a satisfactory degree, somtimes when you know the rules & break them, and other times when you don't know & go ahead & do something & it works.

  6. #6

    DIY graduated filters?

    We send stuff out at work to get sputtering done. Usually a coating of ITO to maintain an EMI/RFI screen across a display window. I don't think it's the sort of operation you want to try at home though!!

    For optimum optical quality, you obviously don't want to be manually applying stuff to glass - that's what money and photographic shops are for. However, for experimenting, anything is valid.

    Steve Smith.

  7. #7

    DIY graduated filters?

    haha that first techneque doesn't quite sound diy for my standards! so i guess i could go out and buy some glass paint and try the dipping technique!But i'm thinking that will probably create smears or be slightly uneven,
    I'm surprised that i can't find anything on diy filters because people seem to be diy'ing everything these days!I've even made my own lcd projector, but i can't seem to work out an effective way to colour glass!It sounds stupid really!

    I wanted to go DIY so i could have a filter for every single situation that i would come across, are there any cheap companies that do lots of varied shaped graduated filters? (UK if possible) or are there any other products that can be used as grad filters?

    cheers for your replies guys

  8. #8

    DIY graduated filters?

    You could try Lee Filters. They make quite expensive (but good) filter systems. They also make coloured gels for stage lighting.

    I have here a sample book of their lighting gels. It is actual samples about 1.5" x 3.5" of gels in every colour you can imagine and includes some neutral densities. If this booklet size is too small they sell them to theatres in sheets about 3' x 4'. Your local theatre may be able to supply you with some colours but they would be unlikely to use the neutrals though.

    They could be cut to the size and shape you want and attached at the edges to a support -glass, etc.
    I have some fairly stiff 1mm clear polycarbonate sheet which might do. If you would like some, send me your address in a private message and I will post some to you. Let me know what size you want and I will cut it - perhaps cut to fit a Cokin holder would be a good idea?


    Steve Smith.

  9. #9

    DIY graduated filters?

    DIY graduated filters? Wow, that sounds like a challenging project. I have *no* experience with that, but for whatever (little) it may be worth, this is what comes to mind.

    For glass paint, you might find it easier to take paint off to form a smooth graduation than to put it on that way. Paint the glass (maybe by dipping), let it dry, then use cotton with a weak solvent to blend the paint to clear. Using some sort of mild polish to blend the paint layer to clear might also work.

    An airbrush might work for creating a graduated paint layer, though it might come out with a matte surface. Polishing might help if the layer is durable enough.

    If the grad is linear (like the standard grads used for sunsets and such) the dip technique might work if the paint is quite thin. You might try a series of dips, the first all the way to the edge of where you want the grad, the next dip (after the first has dried) a bit less deep, the next a bit less, etc. That assumes that a dip doesn't attack previous layers and simply wash them off.

    Keep in mind that if the filter is placed very close to the lens (and you don't use tiny apertures), the grad probably doesn't have to be perfect to work. You might even get by with using a gel or acetate filter covering only part of the aperture. If that's too sharp you might try a stack of optically-thin filters (i.e. weak color) with the edges offset to form sort of a step filter. If it's sufficiently out of focus that might work.

    Ramblings that may or may not be worth trying....

    BTW I assume you've had a look at Cokin filters? They have the cheapest grads I've seen.

    Good luck, and if you come up with something that works please let us know how you did it.

  10. #10

    DIY graduated filters?

    wow the taking off of the paint is such a simple but possibly effective way of doing it, would be much easier to get a whole peice of glass to dry smooth and level and then take away than do lots of layers trying to keep everything smooth!! I'll be looking into that!

    Just need to find somewhere local that sells decent glass paint!Ili live in a pretty tiny town (at uni) so will have to venture further to find some decent craft shops or such like!

    thanks for the offer of the polycarbonate steve, i won't deprive you of it just yet, but if i do actually manage to make anything usefull i will probably request it from you!

    If the guy from the decalogue made 600 filters like 20 years ago, i should be able to make a few now (hopefully) haha

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