CurtPalme.com Home Theater Forum

Spanky Ham · Joined: 22 Mar 2006 Posts: 5643 Location: Comedy Central

I was thinking (I know that can be dangerous) recently when looking at my 909s with clear C-elements that there must be a good way to get Rec709 out of them. I saw Craig's test that he did with the red element. I think he also tested the green element. Since colored c-elements are no longer available, I was thinking that maybe using colored glycol might be an alternative. Furthermore with the ability to change the color more easily, it shouldn't be difficult to get REC709. Any thoughts?
https://www.curtpalme.com/forum_archived/viewtopic.php@t=13984.html
http://www.curtpalme.com/Tinting_Glycol1.shtm

ecrabb · Posted: Thu Oct 07, 2010 4:09 am Post subject:

You can't do that, Spanky... The magnitude of color filtering would change with the volume of tinted glycol, from thinner/lighter in the center to thicker/darker at the edge of the lens.

SC

garyfritz · Joined: 08 Apr 2006 Posts: 12088 Location: Fort Collins, CO

I wonder if there's some way to dye the C-element itself?

**AnalogRocks** · Posted: Thu Oct 07, 2010 4:22 am Post subject:

window tint film

Spanky Ham · Joined: 22 Mar 2006 Posts: 5643 Location: Comedy Central

stefuel · Posted: Sat Oct 09, 2010 10:27 am Post subject:

I tried to dye a c-element once and it did not work well. I have had luck with other plastics though.

If you were really carefull and clean, I bet you could sandwich in some photographic gel filter within a lens pack inside a HD-10 lens.

Taking a lens apart is not that hard. What really sucks is getting them back together without any dust particles showing.
I did three lenses once that had gotten wet and had fogged up inside. It took me a whole day.

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

If you have a clear C element to experiment with, you might get satisfactory results by having it clear coated with clear red or green paint in the proper shade. You'd start by doing paint samples on clear plexiglas and placing them in front of your lenses purely to check the color coordinates that result.

Then, if you're not a really good painter, have a professional automotive painter do the spraying.

I'd do it with tinted clear urethane. SEM or House of Color for the tint.

It would be very important that the paint is sprayed with excellent technique, so as to give the smoothest possible finish.

I have a spare pair of red and green C elements. I might be interested in selling them. They're pristine and stored in the correct
C element plastic holders.

CJ

virusc · Joined: 11 Apr 2007 Posts: 358 Location: Massachusetts

does the filter have to be before the c-element or after the last one? If not what about taking apart the lense and adding the filter between 2 elements that are liquid coupled?

draganm · Joined: 08 Mar 2006 Posts: 8990 Location: Colorado

Spanky Ham · Joined: 22 Mar 2006 Posts: 5643 Location: Comedy Central

Nash and I were talking and I think he came up with a good idea. What about putting a filter on the tube face? At least I think you said that Nash, if not then I am attributing it to you anyway. Smile

Will glycol dissolve the gel filters?

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

Hey, along those lines, if the glycol is compatible with urethane paint, just clearcoat (tinted clearcoat) right on the CRT face. That should work just fine. I'd experiment with getting the right shade by finding an old CRT RPTV with fairly good tubes. Use that as the painting experiment.

CJ

garyfritz · Joined: 08 Apr 2006 Posts: 12088 Location: Fort Collins, CO

There are some theater-lighting gels that do a pretty good job of color-filtering, see e.g. https://www.curtpalme.com/forum_archived/viewtopic.php@t=5604.html Trouble is, they're not optically perfect. I thought they added a bit of "filminess" to the image, but I could have been mistaken. It's cheap to try if you want to experiment, though I have no idea how LC lenses are put together & no idea if you could slip a gel in there. No idea what glycol would do to the gel, either.