Following on from my blog posting titled Odds and Ends In B&W Film Development I thought I would continue with the topic of the final rinse.
Final Rinse Update – In the past I had spots now none:
The final rinse is 3 minutes in distilled water; After the 3 minutes I
then add 1 drop of Edwards LFN wetting agent.; Shake really well for 5 seconds, wait until any foam dies down; Then remove film from
liquid. Shake off excess water and hang to dry.
Absolutely no spots!
Notes:
The distilled water adds about $0.15 per roll but it seems to be worth it, The trick seems to be prior to adding the wetting agent leave the film in the distilled water for long enough to dilute (replace) any of the tap water in the emulsion.
Over washing and washing the film like a raccoon can do irreparable damage to the emulsion.
Obviously if you get white spots with tap water you need distilled for the final rinse if you don’t get them then you don’t.. And of course negatives without white spots and drying marks are better than those that have them.
I did an experiment watching under a microscope one drop of distilled water and one drop of my tap water dry on a microscope slide. Absolutely no observable difference! So why use distilled water? Distilled water removes most minerals from the film gelatin layer so it doesn’t come to the surface later and cause water marks when it drys. The final rinse must be long enough for the gelatin to become in equilibrium with the rinse water. The reason I reuse the same “distilled” water from the final rinse for the photo flow or wetting agent stage is that I want the water within the gelatin to be in equilibrium with the water that has the wetting agent. This and a short cycle time with good agitation keeps the wetting agent surfactant mostly on the surface where it belongs.
It’s all about chemistry, surface chemistry, diffusion and equilibrium.
Why not dishwashing soap instead of a wetting agent? Because it’s a false economy and they contains impurities, contaminants that could cause problems. Wetting agents designed for film do not have the extra impurities that are added to dish water soaps and are only a couple of pennies per film.
Tip:
Sometimes I find stuff floating in my developer or fixer, to remove pore the liquid through a small fine stainless sieve used for cooking. Don’t forget to rinse the sieve after using to prevent corrosion.
Drying
I recently I brought an old Kindermann Rapid dryer. I then taped a dust and pollen filter over the fan air inlet so for a total cost of $20 I can now have dry, dust and spot free film ready to scan within 45 minutes of development.
There are many DIY dryers out there on the web including those made with garment bags. This MacGyver like method although I haven’t tried it yet, it looks brilliant!
Warning
Depending on your water the use of distilled water may be dangerous overkill. A friend of mine after many years of no problem started to have problems with spots this went on with the spots getting worse over the year, Finally he gave me a spotted frame which under a microscope showed fine surface crazing all over with the spots caused by more severe surface damage rather than by left over chemical residue. With the proof he finally followed my advice and used the Ilford method of rinsing. Suddenly no problems! His problems started when in his own words “Someone told me I should rinse more so I started to rinse more and the more I rinsed the bigger the problem so I added more rinsing aid and more distilled water. Ended up rinsing like a Raccoon.”
References
Why Is Water The Universal Solvent
Diffusion
Surfactant
Well priced alternative to a flatbed scanner.7200 dpi scanner (when measured with a target it turns out to be 3800 dpi in both directions which is right in Nikon cool scan territory)
Actual Dmax > 3.6 and can be increased through multiple exposure mode.
The Negative:
Scanning is done through the included Silverfast Se plus software.
Manual feeder so after you load the carrier you have to push it through by hand one frame at a time. This is not really a problem as I hand correct every negative
No digital ICE (not really a problem for me as I don’t use it anyway and it doesn’t work on B&W)
My Findings:
If you have any form of workflow the Silverfast software is a piece of junk you would have to spend at least the cost of a scanner to upgrade to a usable version. Besides a rather useless raw mode it doesn’t have 48 bit per colour save function. The raw mode would be good if it integrated with lets say Lightroom but it doesn’t. It’s designed to work with another pricey piece of software you have to buy from them. I don’t know about you but I only like to scan once and use the file as a master.
To top it off they keep on telling you to read a 500 page manual and strongly implying that if you want to be a pro you are using the wrong scanner software.
The solution is easy buy reasonably priced Vuescan software. The pro has lifetime support, useful raw workflow and can support multiple scanner types.
Scanning B&W I used some nice grainy HP5+ and found out this:
Multi-exposure is effectively a two pass scan with each scan taken at a different exposure, the 2 passes are then blended together. This actually works and extends the dmax and dynamic range for difficult frames. There is a slight but noticeable lose of resolution. most of which can be recovered with some of the hated USM filtering. Not much need for this function with HP5 I will have to wait until I test it on some high dynamic range shot using TMAX film.
The raw scans pre-adjusted with a film profile seem to contain all the tone information with no banding or noise. Thus they can act as masters.
For 3600dpi scans there was marginally better detail and micro-contrast when scanning at 7200dpi at letting Vuescan reduce the output to 3600dpi (down sampling). This seems to be real not some USM shapening slight of hand (USM was off). Makes sense as the measured on a target dpi is 3800dpi and downsizing by 2 is equivalent to multiple sampling without the alignment problems.
As scan time is almost 4 times as long at 7200dpi I will use 3600dpi scans on images that I don’t care so much about and 7200dpi down sampled to 3600dpi on images that look interesting.
Also of slight interest was that letting the software convert from the colour scan to BW gave slightly better micro-contrast then converting the 48bit colour to 16 bit B&W after the fact or scanning in 16bit B&W.
I tested the same negative on my Epson V500. The Epson had less then half the actual resolution and more compression in the grey scale. The hp5 film grains were blobs instead of salt and pepper with the Plustek.