[tl;dr: Nice tank, some issues, one of which could be a deal breaker if caused by the design.]
I was happy to receive my SP-445 after contributing to the campaign and watching its evolution. I must admit I was disappointed to see the design move from a plunger based agitator to an inversion tank, but it still retained a nice compact footprint.
The received unit came fully assembled, nothing to do but use it. The holders did show a miniscule amount of curve, discussed in other threads. It didn't seem to be an issue, and certainly wasn't an issue for loading sheets.
I first tried the tank, lights on, with water, to see how it handled fluids. Unlike it's closest competitor, the now abandoned HP-CombiPlan, this tank takes on the chemistry very rapidly, and it appeared to flow smoothly from the pour-in side, through the baffles, and onto the film. One could fill the tank in a small number of seconds - it takes the liquid as fast as you care to pour it. But this could be a problem - more on that later in the review.
I followed the directions carefully for placing the lid on top - wetting the seal first. Then to some inversions, using water. Unfortunately, even with the best care, this tank leaks a bit intermittently during inversions. I held it at the top to assure the lid wouldn't come off, and didn't unnecessarily squeeze the tank. But leak it did. Not enough to ruin a development session, but enough to justify doing your work over a sink to catch the drippings, and to wear gloves.
My experience during development with regard to leakage was a bit mixed. It didn't leak with every inversion, so I'm sure it does have something to do with pressures by the hands, but it isn't clear what causes it or how it would be avoided. The seal is one o-ring on a press-fit lid. There is a large area to seal, and it is sufficiently thin plastic that some movement of the surfaces around the seal could easily account for such leakage during handling.
During development, a 5 minute period, the tank lost 15ml of liquid. It lost less (miniscule amount) during stop, and also less during fix (I didn't measure it, but less than 10ml).
I would note too that the lid on my unit does not sit flush against the top of the tank. There is about a millimeter gap between the lid flange and the top of the tank. The lid can be pressed flush, but it naturally rises back up to this gap. I'm not sure if this is the cause of the leak. Here's a photo of the gap:
Leaking is the primary reason I was hoping the plunger agitation would work. I really don't like leaky tanks.
On to the results! I processed two test images taken the same day on Fuji Acros 100. I shot a scene outside, in extremely contrasty light, just because. Due to the result, I will do another test indoors with a controlled scene and lighting.
After development, I <cough> s c a n n e d <cough> the first negative to evaluate it carefully for even development. I did not see the streaking reported in another thread. Unfortunately, I found one disturbing area in the image, which I've indicated with an arrow:
(EDIT: The negative was inserted into the holder upside down, so this area was near the bottom of the tank.)
I suspect this is due to overly strong fluid flow when I poured in the developer, but I have no way to prove it. It has the look of a light leak, but I have confidence in that film holder and in my technique. The spot on the negative is roughly aligned with a port on the tank's baffle. I do note though that the negative on the other side of the same dev tank holder doesn't appear to have the same flaw. So I'm not ready to declare that this is a repeatable flaw in the design. It does tell me that I can't yet depend on this tank for critical images until I've done further testing.
One other oddity, that only exists with this negative: The tiny tabs that hold the negative secure in the holder left little marks on the negative. It appears that fluid didn't get under the tabs during processing for some reason. I don't know if this is the result of the slight curvature or something else. I will note that I don't generally do a pre-wash before development - this may convince me to do otherwise with this tank. Both issues might be mitigated by getting the negative wet before adding developer.
It is possible that the slight curvature of the holder might account for both of the above issues. A slightly convex holder would press the film against the tabs, and would also expose the film more directly to the flow. I'll attempt to straighten the holder perfectly before conducting more tests.
Bottom line is this: it is, overall, a nice design, and should be a good addition to my darkroom. I'm glad I bought it. However, until I'm confident it can repeatably perform on my most critical negatives, I'll stick to my lights-out dip and dunk process. In the mean time, I look forward to the advice of others, and to input from the designer of the tank, to help me refine my technique with this new tool or debug the unit itself, whatever is required.
I was happy to receive my SP-445 after contributing to the campaign and watching its evolution. I must admit I was disappointed to see the design move from a plunger based agitator to an inversion tank, but it still retained a nice compact footprint.
The received unit came fully assembled, nothing to do but use it. The holders did show a miniscule amount of curve, discussed in other threads. It didn't seem to be an issue, and certainly wasn't an issue for loading sheets.
I first tried the tank, lights on, with water, to see how it handled fluids. Unlike it's closest competitor, the now abandoned HP-CombiPlan, this tank takes on the chemistry very rapidly, and it appeared to flow smoothly from the pour-in side, through the baffles, and onto the film. One could fill the tank in a small number of seconds - it takes the liquid as fast as you care to pour it. But this could be a problem - more on that later in the review.
I followed the directions carefully for placing the lid on top - wetting the seal first. Then to some inversions, using water. Unfortunately, even with the best care, this tank leaks a bit intermittently during inversions. I held it at the top to assure the lid wouldn't come off, and didn't unnecessarily squeeze the tank. But leak it did. Not enough to ruin a development session, but enough to justify doing your work over a sink to catch the drippings, and to wear gloves.
My experience during development with regard to leakage was a bit mixed. It didn't leak with every inversion, so I'm sure it does have something to do with pressures by the hands, but it isn't clear what causes it or how it would be avoided. The seal is one o-ring on a press-fit lid. There is a large area to seal, and it is sufficiently thin plastic that some movement of the surfaces around the seal could easily account for such leakage during handling.
During development, a 5 minute period, the tank lost 15ml of liquid. It lost less (miniscule amount) during stop, and also less during fix (I didn't measure it, but less than 10ml).
I would note too that the lid on my unit does not sit flush against the top of the tank. There is about a millimeter gap between the lid flange and the top of the tank. The lid can be pressed flush, but it naturally rises back up to this gap. I'm not sure if this is the cause of the leak. Here's a photo of the gap:
Leaking is the primary reason I was hoping the plunger agitation would work. I really don't like leaky tanks.
On to the results! I processed two test images taken the same day on Fuji Acros 100. I shot a scene outside, in extremely contrasty light, just because. Due to the result, I will do another test indoors with a controlled scene and lighting.
After development, I <cough> s c a n n e d <cough> the first negative to evaluate it carefully for even development. I did not see the streaking reported in another thread. Unfortunately, I found one disturbing area in the image, which I've indicated with an arrow:
(EDIT: The negative was inserted into the holder upside down, so this area was near the bottom of the tank.)
I suspect this is due to overly strong fluid flow when I poured in the developer, but I have no way to prove it. It has the look of a light leak, but I have confidence in that film holder and in my technique. The spot on the negative is roughly aligned with a port on the tank's baffle. I do note though that the negative on the other side of the same dev tank holder doesn't appear to have the same flaw. So I'm not ready to declare that this is a repeatable flaw in the design. It does tell me that I can't yet depend on this tank for critical images until I've done further testing.
One other oddity, that only exists with this negative: The tiny tabs that hold the negative secure in the holder left little marks on the negative. It appears that fluid didn't get under the tabs during processing for some reason. I don't know if this is the result of the slight curvature or something else. I will note that I don't generally do a pre-wash before development - this may convince me to do otherwise with this tank. Both issues might be mitigated by getting the negative wet before adding developer.
It is possible that the slight curvature of the holder might account for both of the above issues. A slightly convex holder would press the film against the tabs, and would also expose the film more directly to the flow. I'll attempt to straighten the holder perfectly before conducting more tests.
Bottom line is this: it is, overall, a nice design, and should be a good addition to my darkroom. I'm glad I bought it. However, until I'm confident it can repeatably perform on my most critical negatives, I'll stick to my lights-out dip and dunk process. In the mean time, I look forward to the advice of others, and to input from the designer of the tank, to help me refine my technique with this new tool or debug the unit itself, whatever is required.
Last edited:
I always wear nitrile gloves when handling any photo chemicals. Therefore, mine may have leaked a little and I didn't even know it.
