Hey fellow lithers, and more specifically the MGWT lithers,

I need a bit of help. I got some MGWT and have had some great success with the paper and really want to see what all I can do with it. However, I have two problems I can't figure out. I want to make sure it's clear that I am contact printing with ambrotype (collodion on glass). This might or might not be contributing to the issues. These are not intensified or developed as a negative but regular ambrotypes meant for black backing. I've had no problem with fomatone and fomabrom. I'm exposing with a 40W bulb with a piece of cardboard over it with a hole punched in it. It's 2ft above the print.

Unfortunately, I purchased arista lith developer at the same time and so I don't know if that is part of the problem. I thought for sure it was because switching to LD20 it went away. I had read about the tricky snatch point so I know about that and the 'explosion' in the fixer. Having said that, on to the first issue.

This is with arista lith, 70:70:2000 with about 250ml old brown (from a frustrating session with fomalux). As the development progressed, I could see the image fine but there was the foggy layer. Well it didn't really go away. It was like a mottled scum layer. The weird thing is I could see the infection(albeit slow) progressing 'under' this scum. Being new to the paper I thought this was the stuff that would clear off in the fix. It actually looked like the type of stuff that would. Well it didn't..... The very strange thing about the arista bath is it would go REALLY yellow quickly after a few 4X5 test prints (in 2L dev bath). That's totally different than LD20 so I thought it was definitly the arista. I had similar issues with arista and fomalux (different story.....)
Stop bath is 1%acetic and the fix is 1:7 Clayton archival rapid fix. (2 baths).
Attached is an example of the mottled scum.
IMG_20120907_204623.jpg

I switched to LD20 and I was able to make some prints and learn a bit about the different snatch point. However, toward the end of the session I started to see problem 2 (splotching). It was almost like the inverse of problem #1.
As the development progressed I would see the foggy image (as usual for lith IMO). Then I'd see these black splotches start to come out of the fog. They were in the shadows and mids but completely random from print to print. These weren't blacks progressing from infection but random spots on the print. I chalked it up to warn out developer. I could let it progress and the final image would be fine but the splotches were prominent. See second attachment
IMG_20120909_084620.jpg

Ok, so that is what happen the first session. After reading some things further I wanted to make sure these weren't from contamination. The tray I used has only seen lith developer. However, I was wondering if the arista didn't like some residual ld20 from previous sessions (although I cleaned the tray). So I cleaned the tray well and last night decided to try 40:40:2000 arista with NO old brown (in case it was contaminated). I saw the same problem #1 and quick yellowing of the arista bath.
So I clean the tray again and make up the same dilution with ld20, 40:40:2000 because I wanted to see what colors i could get out of MGWT with the higher dilution. Well that didn't go so well.... I immediately saw problem two. I thought because of the weaker developer I might have to use more exposure than my previous session. I went from 20s to 2min. Then I saw problem #1!!! crap. It was late and I was tired and frustrated and gave up...

Is it possible that overexposure (or wrong exposure) could cause this? That perhaps the arista needs FAR less exposure than LD20? Therefore the high overexposure would kill the bath that fast (seems unlikely)?

Is it possible I got a bad batch of MGWT?

How about the glass causing weird reflections to cause #2? Like a magnifying glass 'burning' areas with extra exposure. If so why would it be mainly in the darks.

Agitation was fine. No edge developing out faster. These were 4X5 test prints in a 12X16 tray so there was plenty of room to move around. The first session with LD20 did produce a nice print that I uploaded.
I was hoping for some gritty grain that I like in lith but it wasn't there. So that might be related to these problems? Also, if you look close you will see the problem 2 splotching to the left of the girls (and elsewhere). It just wasn't that bad at that point and just got worse.

I hope that was clear enough....
Any help or comments will be much appreciated. I ran out of LD20 but have PLENTY if arista....it's 30X less expensive than the LD20. That sure would be nice if it worked for what I want to achieve.

THANKS!
Scott