I had no Time-zero films, just a pack of PX600 and an old Polaroid 600 film. The SX-70 camera works with 150 ASA films while 600 films (as the name says) are 640 ASA. So we have about 2 stop to gain, if you don't want a massive overexposure!I removed the filter out of the photocell to gain maybe one stop (from 0,25 to 1,25 stop).
Anyway, as you can see from the first shot [previous post]... it was not enought (with the Lighten/Darken control on darken too).
So I found a set of gel filter (for flash I think) and one of these could be read "Orange filter, 0.6 optical density" = ND4! (but orange) (a gift of an eBay seller)
I cut a piece and put it on with tape just in front of the lens.
I decided to use the PX600 film cause it's sepia (the filter is orange!) and....it works!!
Look at the 2nd photo [previous post], with directly sunlight and with the L/D control set on darken (the vertical lines are a problem of the IP films). Definitely... the perfection is with the ND4 filter and the L/D control on the center, without the photocell filter.
I'm waitin' for a normal Neutral D4 filter, not orange... (bought on eBay 1month ago for 3$, from India) I have some pack of 600 COLOR film in my fridge...that are waiting!
Canon FD 50mm f/1.8
Fuji Superia X-Tra 400
(scan from print, SOOC)