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SP-8x10+ Sheet Film Processing System
Since launching the SP-445 Film Tank, we've received a constant (well, not maybe not constant but at least very consistent) stream of requests of a larger version. We've tried a lot of different ideas and have finally settled on a tray based system. Why?
- Tray processing has been the main-stay of photography since the beginning. It's simple and reliable.
- Easily accommodates multiple formats: anything 8x10 or smaller.
- Rugged: no seals, moving parts or complicated latches.
But does it work?
A very reasonable question. This is truly a case where a "picture is worth a thousand words." Here's our toughest test case: gray door in the sunlight.
While that proves it works, it is rather boring. Here's an example that's more interesting:
- Process any sheet film, 8x10 and smaller: 1 - 8x10; 2 - 5x7 or 4 - 4x5 or equivalent.
- Max of 1 liter of chemistry
- Daylight safe (obviously, you'll have load in it the dark)
- Fast to fill/drain (prototypes fill in around 10 seconds.)
- Easy to use.
The current prototype is about 275mm x 380mm x 60mm. The production units will be close. We actually spent too much time designing a latch mechanism for the lid. After playing with the alpha model, we realized we don't need one.
The unit fills/drains through three light baffles on the one end. Current times around 10 seconds for 1 liter.
We hope to reduce the chemistry requirement but frankly, we aren't too worried about it. Let's just be blunt: if you're worried about 700 ml vs 1000 ml of solution, maybe you shouldn't be shooting 8x10.
Obviously, our current design for the pallet is close relative of existing film holders for the camera. Note that we're still experimenting with landscape vs portrait orientation. Right now we're planning on separate pallets for the different sizes (5x7 vs 8x10) but that could change.
We're also planning a DIY kit as a post-Kickstarter option. This would include a blank pallet and an assortment of film guides. You'd just glue the guides down in whatever configuration you needed. It would probably include guides for glass plates as well. Before you ask: yes, we considered adding this as a "stretch goal" but decided not to:
- First, it will complicate the development process: it means another mold, more testing etc. We want to focus on getting the fundamentals right; then worry about the bells and whistles.
- We know that a lot people want an 8x10 pallet, and a bunch want a 5x7 pallet. But after that? We're just guessing. We have no idea regarding the market size.
- To be honest, it's not that hard to build your own. A piece of plastic and a few hours in your shop and you'll have any size you need. Of course, if you have a decent 3D printer...
On the subject of glass plates, you might get away with dropping one glass plate in the tray, as long as you don't tilt the tray too steeply when draining it. Add more than one and they'll probably crash into each other during agitation and you'll have glass shards everywhere.
(Editor's note: we're calling them "pallets" to avoid the confusion we've run into with the SP-445: are you talking about the film holder in your camera or the film holder for the tank?)
We are researching the possibility of stacking two film pallets. This would allow you to process two sheets of 8x10 (or equivalent) at a time.
- Initial testing indicates that this won't be trivial. It's going to take some magic or really innovative engineering, (same thing).
- Feedback from pre-announcement partners indicates that it isn't a really big deal. Most of them only process one sheet at a time anyway. The SP-8x10+ will be perfect for photographers that take one shot at N-1 exposure and the next at N+1. However, it would be a time saver for many and we'll investigate it seriously.
Here's a short video addressing the most common comments so far:
Change is expected.
Don't ever forget that this is a development project (ignore the pun). We're expecting things to change as we move forward with more testing, gather feedback from backers and refine the design. (Take a look where the SP-445 started and where it ended!)
Also, note that legally speaking, you're not purchasing a product (hence no sales tax, at least not in the US); you're funding a research/development project. While we believe the latest prototype is really close to the production version, things could change.
Risks and challenges
Frankly, there isn't anything that new here and we don't foresee any major risks. (A dangerous thing to say!)
That said, we do have some minor concerns:
1. Optimizing the film pallets.
2. Perfecting the agitation procedure. It's one thing for it to work fine in our lab but another challenge to get it working perfectly with every combination of film, chemistry and photographer!
3. We REALLY want to process two sheets at a time but we don't know how much effort it will take to perfect the process. It might have to wait for a future upgrade.
Another issue will be shipping. The SP-8x10+ is lightweight but bulky. This makes shipping more expensive (we'll get hit with "dimensional weight" charges.Learn about accountability on Kickstarter