Workprinter/transfer constrast ideas :

Basstruc not logged in · Sat Mar 08, 2003 7:25 pm

Since video cameras cannot reproduce the high contrast of kodachrome, I tought about some solutions in order to get the most informations of the emulsion when transfer :
1 ) Put a contrast reducing filter in front of video camera lens or projector lens : Tiffen low contrast, unltra contrast, black promist, ect ....
cons : I never saw very effective results from those filters. Maybe you did ? please post your experiences about it
2 ) The cheapest solution : do several pass of the film : one on normal exposure, one for highlight ( if whites burnt through the transfer ), one for shadows ( If informations lost in deep blacks ). Then, from the normal exposure pass, do luma keys with black or/& white from underexposed, overexposed pass.
Cons : Might not work very well, might be awfull but since it's free, would be interesting to give it a try. Please post pics
3 ) For Roger : build a cheap varicon style flasher. Replace the mirror by a semi-alumined mirror ( don't know about the proportion, maybe 80/20 or 70/30 would be great ), then, behide to the mirror, put a diffusion glass ( or plastic ) with behide some tiny neon lights ( great because can reduce light through a dimmer without color temperature changes ). Sorry, I'd loved to do shematics but have no scanner connected to my computer. The flash produced would clear shadows areas. The most interesting solution in my point of view.
Cons : Semi-alumined mirror might be expensive if just a few pieces bought, but not if it's a large quantity. Might be a problem with shutter frequency of the video camera ( tought I never had any problems by filming with neons )

Matt

Basstruc not logged in · Sat Mar 08, 2003 7:28 pm

PS : The flasher would also permit to use gelatine filter in front of it so that you can get tinted shadows, great !

Post by **mattias** » Mon Mar 10, 2003 3:10 pm

Basstruc not logged in wrote:1 ) Put a contrast reducing filter in front of video camera lens or projector lens

i don't think that will work. these filters only work when the contrast is rather extreme, like on sunny days or backlit scenes, while they do basically nothing on overcast days and so on. k40 has a lot of contrast, but not nearly as much as "real life". and even if they would work the soft and misty look they produce might not always be what you want.

2 ) The cheapest solution : do several pass of the film

nobody seems to think this is a good idea for some reason, except you and i and we don't have workprinters to try it with. ;-) i've suggested exactly this a dozen times during the last year and nobody bothered to try it even on a single frame.

3 ) For Roger : build a cheap varicon style flasher.

good idea.

/matt

Royalbox · Post by **Royalbox** » Mon Mar 10, 2003 3:33 pm

nobody seems to think this is a good idea for some reason, except you and i and we don't have workprinters to try it with. ;-) i've suggested exactly this a dozen times during the last year and nobody bothered to try it even on a single frame.

It sounds like a good idea in theory and would probably be easy on a single frame, but I don't think it would be possible to get 2 captures where each frame lines up exactly. You can see the edge of the film frames move up and down slightly as the video plays back. Just touching the video camera to set exposure can move the alignment slightly as the zoom is so high. If I could get a stabelizer to work on just the edge of the frame that might help but I've not had anything usable out of one yet.

However, I will see if I can find a film with very high contrast and post very short clips on my webspace if you like (if you want to try it). I only have dial-up connection.

YouTube · Post by **Andreas Wideroe** » Mon Mar 10, 2003 3:36 pm

mattias wrote: nobody seems to think this is a good idea for some reason, except you and i and we don't have workprinters to try it with. ;-) i've suggested exactly this a dozen times during the last year and nobody bothered to try it even on a single frame.

When I have time I'm gonna try that, but what f/stops should I use? On overexposed and one underexposed and maybe one normal?

/Andreas

Post by **digvid** » Mon Mar 10, 2003 4:04 pm

i've suggested exactly this a dozen times during the last year and nobody bothered to try it even on a single frame.

Actually, I have tried this before. A Dodcap customer modified their WorkPrinter to send out two clicks per frame instead of one, and also added a filter that moves into place for one of the clicks. Note that this eliminates the problem of minute differences in frame alignment that you might see if you made two passes over the film.

I created a modified version of Dodcap that takes two frames from the video stream and "merges" them into one using various methods designed to use some detail from the normal or underexposure and some detail from the overexposure.

We eventually decided not to pursue this, for several reasons. One reason was that it takes a very, very time-consuming post-processing session to merge the frames. It can be done quickly, but only by sacrificing the improved detail that you were trying to get in the first place. The second reason is that you are effectively doubling the amount of time it takes you to transfer your footage with the WorkPrinter, which is already slower than the film's actual running speed. The third is that the whole process of capture and post-processing seemed too complicated for the average WorkPrinter user to be interested in.

Having said that, I do believe that this could work for a hard-core WorkPrinter user that knows what they are doing. The biggest challenges I see would be this:

1) Modifying the WorkPrinter to produce two clicks and move a filter in place.
2) Setting up a dedicated computer system that is efficient enough to capture two frames (instead of one) at a reasonable speed.
3) Gaining access to an exposure-blending algorithm that is effective enough to produce better results than what you would get by simply using a good three-chip camera.

- Jeff Dodson

Royalbox · Post by **Royalbox** » Mon Mar 10, 2003 5:04 pm

Excuse my ignorance, but what is a varicon style flasher?

Jeff:
Any news on the Dodcap update with the 'mouse lock' feature?

Post by **digvid** » Mon Mar 10, 2003 5:54 pm

A "Vericon" is a brand of trench coat, so I am guessing that a "Vericon-style flasher" is a man/woman who flashes using this type of coat. I hope I never run into one of those...

The version of Dodcap with the mouse lock is finished, included the help which I have updated. However, I have delayed releasing it because I can't seem to find a computer that I can adequately test Dodcap on. I have a laptop that runs Dodcap fine, but the hard drive is an old 4200rpm ATA/33 that is tool slow to run at 6 fps, and my wife's aging computer has a BIOS bug that causes the computer to lock up every time any sort of video capture or disk-intensive activity takes place. My main computer died a few weeks ago, and I am currently spec-ing a new one, which I hope to get this week. After I get it set up, I will finish the Dodcap testing and release, probably some time next week. Sorry for the delay.

- Jeff D.

Basstruc not logged in · Mon Mar 10, 2003 11:32 pm

Digivid, are you joking or not ?

Varicon, not vericon, for Variable Contrast. It's pretty much like the system I discibed :
http://mywebpage.netscape.com/markwoods9/Flasher.html

matt

Post by **digvid** » Mon Mar 10, 2003 11:43 pm

Sorry Basstruc...I was just joking about the flashers :lol: !

Of course, I was quite serious about the exposure blending.

- Jeff

Royalbox · Post by **Royalbox** » Tue Mar 11, 2003 1:01 am

Thanks for the link Basstruc I'll have a read of that. Thanks also Jeff for planting that image in my mind!

Filmshooting

Workprinter/transfer constrast ideas :

Workprinter/transfer constrast ideas :

Re: Workprinter/transfer constrast ideas :

Re: Workprinter/transfer constrast ideas :

Already Tried It

Flashers

Sorry...