Simulating Ground Glass noise for pick-up shots

[ciné-ernesto]

Hi all,

We filmed a short in 2005 with an entirely home-made adapter rigged on an-upside-down, video-assisted PD-170. The little film never got finished for several reasons, but now there is a strong mobilization on the part of the people involved to finalize it. The footage from back then actually looks pretty good, even though it was a static ground glass. For some reason it looks right. The GG I used was purchased straight from a lab. Now, to finish editing the film we have to do some pick-up shots, which I intend to do on a D90. My main concern is with the discrepancy of the two textures. I am certain someone must have tackled this in the past, but what would be possible approaches for simulating static ground glass noise (in after effects, or in final cut, or on the camera set-up...) in this new footage?

Any advice is welcome.

Peace, Ernesto.

[cheezweezl]

if you want the static ground glass grain, there are plugs that add grain and some have a "static" option. otherwise, you could find a similar texture in a still and overlay it with blend mode set to darken, maybe..

this would be much easier in AE than FCP

[Ted Ramasola]

cheezweezl is right, AE is a more controllable environment for creating this effect than NLE's. There is also a noise and grain filter in AE that you can choose from. The grain and noise filters has several tweakable parameters that you can adjust to approximate your gg grain.

Ted

[ciné-ernesto]

Thanks a lot guys. I'm certainly planning on using after effects for it, i just mentioned FCP in case someone knew a special fcp plugin. From already trying a little bit I see that the hardest part is to make the grain diffuse light in the specific way that the GG does. And also, what I am having a lot of trouble with is replicating a kind of very soft venetian blinds stair stepping artifact produced by filming the static ground glass with the camera on the "progressive mode" (does any one know how to remove this?, some type of frame-rate conversion or deinterlacing of sony's "fake" progressive? because I guess it would be simpler).

[cheezweezl]

that's the key. adding grain is simple. making clean d90 footage look like the diffused footage from an adapter is a little more tricky.

why not shoot your pickups with an adapter? do you still have it? i have an old static adapter i made. sounds like the same thing u had. my gg came from "optosigma", a company that makes optics for scientific use. it has a canon fd mount on it. wanna buy it?

[DEPTH OF PHIL]

Thanks a lot guys. I'm certainly planning on using after effects for it, i just mentioned FCP in case someone knew a special fcp plugin. From already trying a little bit I see that the hardest part is to make the grain diffuse light in the specific way that the GG does. And also, what I am having a lot of trouble with is replicating a kind of very soft venetian blinds stair stepping artifact produced by filming the static ground glass with the camera on the "progressive mode" (does any one know how to remove this?, some type of frame-rate conversion or deinterlacing of sony's "fake" progressive? because I guess it would be simpler).

Here's quick fix for you , Film Grain Process plugin for FCP from Paul Crisp
This filter can be set to act like a static adapter film grain and can be adjusted in amount and opacity and grain blur. You can also diffuse it with soft focus, g blur etc... Joe's filters have some greta diffusion filters as well.

RE: stair stepping artifact

This sounds like a conversion through compressor reverse the progressive scan to interlaced, but i'm not quite sure what you mean exactly , Any thoughts guys?

[ciné-ernesto]

Hey cheezweezl, wow, it looks like we built pretty much the same thing, down to the FD mount! Thanks for your offer, I'll think about it. I actually lend my adapter after we shot this film to some folks who made a great little short called "Eisestein" with it on a DVX100 that was eventually blown up to 35mm and shown on many festivals, but these friends ended up scratching my GG and I never got around to fixing it. At that later moment I was using a focusing screen setup, which turned out a lot better and cheeper than the optosigma solution - I think it was optosigma, but come to think of it I can't be 100% sure.... In any case, I was using this lab GG without an achromat. Well, since I'm new to this section of the forum, I might just as well finish up my story: I was making this adapter in 2004/2005, around the time this section of the forum was starting. Back then people were calling them mini-35. I was working on it in Recife, Brazil, now I'm in New York. I've always actually wanted to say hi in here, I've just been... shy. Thanks for the welcome, by the way.

In any case, the fact is I already shot some pretty intense and unique things that we want to incorporate in this final cut of our never-ending short, and they are already done with the D90, and it worked so well right now... Don't get me wrong though, I am still going back to setting up good adapter to use on panasonic HighDefs, but for now, I just need to finish this film with what I have in hand ... And that happens to be the D90, and they aren't that many shots - mostly sky stuff, details of a gas station and some birds, nothing involving the actors.

SO, I checked out Paul Crip's Plug-in (Thanks alot Phil!), and it is indeed great, but, for the record, does not have a static grain option. But since Phil picked this up, I realize I made a mistake. One of my main problems that I should be seeking help for would be to get rid of this "Venetian Blinds+Pseudo Stair Stepping" artifact I mentioned. The thing is, I suppose this must have been a pretty common problem at some point here, but I can't find any references. It has something to do with the Sony "Progressive ScaM" mode. Do you guys know if someone found a good remedy for it? Because this could doubly solve part of my matching textures problems. I'd be only left with the grain, but frankly, this is more serious! To describe it better: this is an effect that is there in any ProgScan shot made with the old PDs, but with the Adapter it appears to have exacerbated. I just never knew how to treat it. (So Phil, you think I should try interlacing the footage? Or maybe re-de-interlacing it ? (supposing it is really progressive) Or maybe I could just throw it all in a blender and see what comes out).

All right, I'll wait now.

Best to all.

[DEPTH OF PHIL]

Okay time to get geeky, My immediate thoughts are...

RE: Static Grain,

You should be able to closely emulate static grain through Paul crisp, For instance if f use a still frame and you do a software zoom on it, you can add this filter to add grain to the shot , use the blur grain to diffuse it. you can use "diffuse highlights "filter from Joe's Filters to soften the spectral high lights to give it a adapter look.

RE: Stair Stepping
I'm afraid i'm still not quite clear on the concept,

What is your shooting format, , progressive or interlaced? HD or SD?
What is your final output, progressive or interlaced? HD or SD?
It has to one or the other, for example you wont get those problems ( V blinds) with interlaced unless you freeze on half a frame, 1 field and if you play interlaced content on a progressive scan display. Does all the footage do this or just the new stuff?

If you play progressive on interlaced you will get jumbled stuttering problems.

1)Try and play around with de-lnterlacing , interlacing them in FCP, try shift fields filter , it should choose by it self, What are your edit sequence settings set to ? It will shift accordingly

2)You can convert progressive scan to interlaced through Compressor and Interlaced to Progressive as well.

But small lines (like venetian blinds) visible on your computer monitor usually are "lnterlaced playing on a progressive scan display. If you look on your NTSC monitor it will not be present. This will only look like this on your computer display or progressive screens. Hence , what is your output intended for? Try variables and you will nail it!

Cheers and Good Luck.

[ciné-ernesto]

Hey, thanks,

About the Grain, I'll certainly take take your advice all the way.

About the Venetians, they are on the old footage (yes, this could get confusing because the D90 does also have a stair-stepping problem, but it's very different). And I know what you are saying about the modes, but this is different as well. This was a PD-170, so it's SD, and it was shot on a mode that sony called "Progressive Scan" on the PD-150 and PD-170 cameras (supposedly progressive, then). I think some Canon cameras at the time had it too (like the GL1, if I remember well). So if it's progressive, and the monitor is progressive, than the problem is elsewhere. This type of artifact I'm referring to is something you see when video shot progressive is broadcast on normal TV's. For instance, once I made a TV commercial with this camera (PD) and it was very sunny so I added this on purpose just to get that extra flicker (it's prone to happen more on highlights and high-contrast), but I did it intuitively and I have no idea how it was processed at the TV station. But like I'm saying it gets exaggerated on the GG, it almost looks like ultra-subtle Moiré patterning. It shows the same problem on comp screen and on TV likewise. I'll fiddle around with those possibilities (exporting back and forth via compressor), I'm just asking like this because I'm sure someone must have tackled with this exact same scenario on their ground glass explorations...

[DEPTH OF PHIL]

Hmmm, a suggestion post some footage and/or screen grab, i think this will help us to understand better. Another thing is the shutter speed may be bringing this out more.
Post the problems shots
Cheers

[ciné-ernesto]

Thanks Phil, I solved this specific puzzle already. Just to close this off for now, I figured out the problem, and in case someone has a similar scenario of having used a PD170 on the Progressive Mode, here is the deal: The footage is actually progressive, but Final Cut doesn't interpret it as progressive straight off. Changing the "Format" tab of the Clip in the Browser in FCP to Field Dominance=None made the footage go back to normal. So the Stair-Stepping was not due to the Ground Glass.

Best to all.

[cheezweezl]

sapphire has a static grain plug that is pretty cool.