c_van_sas

This article suggests that purple spots could be caused by inadequate bleaching:

Photomicrography - Color Negative Film Processing Errors | Olympus LS

Ps after scanning the film on a coolscan 8000 small purple spots appeared to be on a lot of locations also when slightly more developer was used. This problem occurred both on fresh Portra and 400h film.

What film are we looking at?

Negative or transparency?

 

The black blob looks like a lump of crud landed on the film before exposure.

 

The other marks look like chemical contamination of the film during development.

 

Air bells or other processing marks usually have a more diffuse edge.

 

Thanks for your response. This is a negative developed in 2y old rollei digibase. Your theory about crud that landed on the film makes sense since there was some crud inside the developer as a result of aging and I unfortunately didn’t filter it. The chance of Chemical contamination would be low since the Jobo system I used was cleaned before and this was the first development of freshly made developer. Maybe the age of the developer could have played a part?

I develop film at home and have tam idea on what might cause this problem:

- I got this problem when not using a pre soak, with a two year old rollei digibase in a Jobo atl. maybe the short development time and older developer caused the anti halidation layer to be not fully be removed. I didn’t experience the problem when using slightly more (10%) chemicals in the tank than recommended in combination with a pre wash of the film before development. Therefore I guess it is a development issue.

 

<p>fccccckkkkk other camera's than Toyo, got no problems here</p>

<p>Same mamiya and epson v700 here and some astia slides.<br>

My experience with the v700 and slides is that chromatic abberation on the borders as well as the unsharp promised resolution that make the scanner useful for the web but not for scanning slides intended to print large ( with negative film its possible to reach larger formats btw ).<br>

I've seen some impessive results on the web of people scanning film with macro lenses but then you should notice that you wont be able to reproduce the same quality of your mamiya 7 lens as the scanner in this case your dslr doesnt have the same quality optics attached ( perfect optics X perfect optics = a little bit les perfect optics ). A lot of folks that tested tons of lenses before they got satisfying results ended up using the nikkor 55mm macro lens or the rodenstock 75mm f4 enlarger lens which was originally intended for duplicating film 1:1.<br>

Now let me do the math for you: <br />If you would replicate your 6x6 film then note that the size of this film would be <br />56mm × 70mm = 3920mm2<br>

The size of your sensor is:<br /> 24.0 x 36.0 = 864mm2<br />delivering roughly 24mp <br /><br>

your sensor would with a 1:1 macro ratio reproduce (3920/864)x24MP=108,88 MP<br />That would richly surpass the maximum resolution you would ever be able to get from your slide film and thereby the maximum highest size of your print.<br>

Good reproduction not only depends on this theory of course in order to mak a good copy of your slides you need to make sure that absolutely no surrounding light leaks tru your lens.<br>

Also note that you should consider how you are going to reproduce the dynamic range of the slidefilm. This is considered to be the main problem in modern scanners. Maybe multi-exposure could offer better dynamic range?<br>

For more info you could read this article of someone who achieved stunning results with scanning by dslr:<br /><a href="http://petapixel.com/2012/12/23/why-you-should-digitize-your-film-using-a-camera-instead-of-a-scanner/">http://petapixel.com/2012/12/23/why-you-should-digitize-your-film-using-a-camera-instead-of-a-scanner/</a><br>

Theres also somebody who automized the proces of shifting the negative ( which comes very precise of course ) by creating his own dslr scanning machine, incredibly cool!:<br /><a href="

Good luck!,<br>

Crispijn</p>

<p>I got quite pleasing results with Provia 100F in my mamiya 7 at iso 100, while my Toyo 4x5 camera delivered underexposed shots at the same rate. It could have to do with bellow corrections and light color ( in morning and evenings provia needs to be corrected +1/3 or +2/3 stop).<br>

Besides that if you do not rely on drumscanners and have a scanner with a limited D-range the blacks in the slides that might reveal a lot of detail that can not be scanned ( f.e. by the epson v700 ). So in order to obtain superior quality I usually overexpose this film 1/2 stop.<br />ISO80 is therefore not a bad standard.<br>

But keep in mind that this is just a rule for personal use. If the contrast in your scene is very high and you would like to get most out of your slide, in order to maintain the maximum dynamic range, you would be better of shooting at exactly the right exposure ( corrected based on the color of the object measured, dailight color, bellows correction etc. ) and then send it to the lab for professional scanning.</p>

<p>The cheapes developer I found untill now is Fotoproekt in Moscow, Russia. They develop E6 for 5 USD a roll. But in contradiction to C41processing which costs me 1,50USD ath their lab its even cheaper for me to process slidefilms my own. I regularly spend $1 - 2$ per roll of film on developing with my Jobo tank system by optimisation of use of chemicals and reprocessing films with the same chems.</p>

<p>Some RB67 owener posted a instuction on how to load the pack:<br>

<a href="http://www.youtube.com/watch?v=dAC2tEQEgFI">http://www.youtube.com/watch?v=dAC2tEQEgFI</a><br>

For me this video in combination with some bad experience made me know how to do it so here some tips:<br>

- load the film as in the youtube movie.<br />- Make sure the paper tabs are NOT folded between the camera back and the polaroid back but all come out of the camera.<br />- Make sure not to waist shots by forgetting to remove the dark slide, the mamiya RZ doesnt communicate with the polaroid back and doesnt know if the dark slide is in or out.<br />- Take the picture and enjoy the result of instant film.<br />- Im shooting a lot in Russia at minus 20 C and the film doesnt develop at these temperatures. Solution:<br />keep the film for the developing time inside your jacket.<br /><br />As a film pack I use <a href="http://www.canemco.com/catalog/Technical_sheets/fp_100c_datasheet.pdf">Fujicolor FP100-c</a>. Fujifilm has as I know 3 types of film for RZ polaroid backs. I don't know if polaroid a.k.a. the ipossible project has different films for the RZ backs.<br>

thats pretty much it. </p><div></div>