How forgetting a simple step could harm negatives. .

<p>The other day when developing my film I forgot to wipe off the excess photo flo on my negatives. They still turned out fine, but I was told not wiping them off could ruin my pictures. How could forgetting this step again harm my negatives?</p>

<p>I never do that. I shake the reel unload it then hang... I try not to ever touch the emulsion when it is wet.</p>

<p>I do the same as Larry, shake the reel, unload - let hang. Usually let hang for at least 24 hours before I cut them and put into negative holders.</p>

<p>I stopped squeegeeing my negatives years ago after I was no longer on deadline. Some wet emulsions are too easily scratched, even by contact with rough spots on my fingers.</p>

<p>It isn't necessary to squeegee negatives anyway. Suspend them diagonally and the water will run off cleanly (a trick I learned several years ago from reading a recommendation by <a href="http://www.rogerandfrances.com/">Roger Hicks</a>). Water sheets off toward the lower edge and drips from the single lowest corner - any water spots that may form tend to be visible only on the margins and won't affect printing or scanning.</p>

<p>Suspending the negs diagonally can be a bit tricky. Plastic clips and bulldog clamps didn't hold securely enough for this method. I use surgical hemostats to clamp the narrow rebates of medium format film, or stainless steel paper clips unfolded into an "S" shape for 35mm sprocket holes. Tension is maintained by rubber bands on either end, one on the shower head, the other secured to a hand rail around the tub. Doesn't need to be guitar-string taut, just enough to prevent too much sagging. Or improvise your own method.</p>

<p>I usually run a recirculating air HEPA filter in the room as well. Keeps dust down and the slight air flow is enough to help negatives and RC prints dry quickly without using heat or other tricks.</p>

<p>Squeegeeing your negs is simply asking for scratches. Photoflo won't damage anything. Even if you use too much, you can always just rinse it off again.<br /><hr>

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<p>Really, just let the negatives drain freely. Don't meddle with a wet emulsion even if you used a hardening fixer.</p>

<p>The film image, after processing consists of microscopic flakes of silver, in the case of black & white film, and microscopic oily globules of dye, in the case of color films. In both cases the image formers are held to the plastic film base incased in a clear coat of gelatin. Gelatin is chosen because it is transparent, flexible, has low solubility, has an open structure that allows fluids to circulate within, and interacts it with the silver salts to elevate ISO.</p>

<p>Now gelatin is hydroscopic. Its water content is about equal to the humidity of the air. Thus it is dry when loaded into the camera and very wet when submerged in processing fluids which are mainly water. When the film hits the fluids of the process, the gelatin swells tenfold. This action is like a dry sponge suddenly wet. After the process the film is hung out to dry. The wet film displays water droplets on its surface and it contains water throughout the gelatin. As it dries the gelatin shrinks back almost to its original dimensions. Now water droplets on the surface retard drying in that local. That translates to the fact that the shrink rate under the water droplet will be different then its surrounds. If this is true, a permanent elevation change will be the result. These are the drying marks you will see on film improperly treaded before the drying stage.</p>

<p>All manor or methods have been proposed and tried to elevate drying marks because once formed the film will be marred and this condition is difficult or impossible to correct. A quick dip and a wetting agent is perhaps best. One can also carefully sponge off excess water. In a high speed machine squeegee rollers and air knives are used.</p>

<p>Anyway the toll for improper handling prior to drying will be substandard film. </p>

<p>I never squeegee. In my early days I tried every squeegee device known to Man and they all scratched the film at somepoint. I just rinse the film in wetting agent and water, then let it drain naturally for as long as possible before turning on the dryer. I prefer either Paterson Acuwet or Tetenal Mirasol at 2 drops per 100 ml water. The trick is to use the least amount which will disperse the water and no more.</p>

<p>Unless your water supply is quite clean, using distilled water with Photo-Flo may reduce spotting prints. I don't even drink my well water, let alone use it for the final film rinse.</p>

<p>I could never resist the urge to put a finger on either side of the film strip and run them once down the full length. With clean, fresh-out-of-rinse-water hands I can't see that having an impact. Sliding strips in my cheap enlarger holder made a hash out of many, though.</p>

<p>Mendel; all it takes is a wayward couple of micron piece of dirt on ones finger; and you have now placed a line through the soft emulsion. Even if you wash your hand there is traces of dirt still down in the pattern on ones skin; all it takes is a piece of dirt or skin to have a rough edge; and the emulsion gets a line in it.</p>

<p>In the contact printing era of MF stuff like 120/620 116/616 for snapshots; a micro scratch was never seen. With 35mm stuff ; 16mm and Minox; a scratch is easier to see; because one often enlarges more.</p>

<p>In some areas too ; ones water has some micro sand in the water supply</p>

<p>In astronomy stuff ones subject can be so faint at is barely above the base fog of the film; and any scratch can equal the signal. If I spend 1/2 hour hand correcting a clock driven time exposure; the last thing I want to add is a scratch in processing.</p>

<p>The simple step of wiping ones wet fragile/soft/wet negatives sounds like wreckless and risky.</p>

<p>Here I just use distilled water and photoflo and hang them up to dry ; and avoid the Russian roulette of wreckless wiping. This was worked for over 4 decades.</p>

 

<p>Most of the "excess" of any solution should be removed by a generous plain water rinse at the end of processing; even the photo-flo.</p>

<p>"Most of the "excess" of any solution should be removed by a generous plain water rinse at the end of processing; even the photo-flo."</p>

<p>Using a plain water rinse defeats the purpose of using photo-flo. Might as well skip it altogether if you are going to do that. A plain water rinse in an area of hard water results in big water spot problems. Even just photo-flo with plain water in a hard water area results in at least some spots.</p>

<p>The best solution I have found is photo-flo in distilled water.</p>

<blockquote>

<p>Using a plain water rinse defeats the purpose of using photo-flo.</p>

</blockquote>

<p>Correct. And, the best practice. Defeat photo-flo! Down with wetting agents!</p>

<p>If one has NO distilled water; using Photoflo can help to massively reduce water spots with tap water.</p>

<p>A lot of people tend to use way way to much , if you only use a very small amount there is no excess to wipe of .</p>

<p>I put about 2 drops in a one liter film tank and one cap full in my cars wiper washer tank</p>