Effects of development. Difference between negatives, slide.

[ciaran_mcmenemy]

<p>I developed Ilford Pan 400 using FD10 (based on 11min at 20'C) and noticed on the scans that the skies are blown, or mostly vague. It's negative film so I'm surprised that this happened (and there is nothing wrong with my technique). Does development time influence contrast, darkness/brightness, or both? I thought it would only influence dark/bright but now I'm not so sure. Oh, agitation was initial 30 sec then three every 30 sec.<br /><br />Another question, what are the physical differences between negative and positive film? I'm wondering this especially since positives are actually made by processing double-negatives. I know E6 film lacks a colour mask - anything else different?<br>

Lastly, why does slide film have much higher contrast (and thus less d.r./latitude)? Wouldn't higher d.r. be better since it is more similar to how we perceive what we see? (imagine looking at the sky with your eyes and seeing that it is 'blown') </p>

[Jochen_S]

<p>Development time does influence the maximum density and that is what your scanner can't cope with. - If you underdeveloped your film the sky should be still inside your scanner's density range. - Development time increases contrast too (as long as the developer isn't totally exploited).<br>

Slides: If you projected a negative, you'd have some grey sauce on your screen. - A "picture" should hold real whites and blacks somewhere to look appealing. to do so a slide needs to have less dynamic range than a negative which has its for exposure latitude to end funneled onto the way smaller (than even a slide's) dynamic range of paper. In the old days they had glass plates to be copied from negatives. - I guess those came with various grades like paper to provide real black and white when projected. - I guess color is basically the same, just more complicated.</p>

[bethe_fisher]

<p>In addition to development time affecting the highlights, if you're looking at scans, you're not looking at the full picture. When I scan negs, I do a decent amount of tweaking before I scan (adjusting the levels to make sure it gets a full range) and after I scan. If you're just looking at a straight scan, it may not have gotten all the detail it could have. </p>

[glen_h]

<p>Color negative films intentionally have a low gamma (contrast), and printing papers have an appropriate high gamma, to make up for it. I suspect that is to allow for use with simple cameras.<br>

(Printing exposure must be accurate, and depends on the negative.)</p>

<p>For slides, meant for projection, there is no way to correct later, so the exposure has to be right.</p>

<p>I am not sure why black and white films don't have the low gamma, other than tradition. Well, at some point you can get a higher density with silver than dye, but still.</p>

<p>I am not sure what you mean by "processing double negatives". </p>

[ciaran_mcmenemy]

<p>I'm confused since when you scan a negative, if it has high d.r. then you would see all the tones, and it doesn't look bad (not to me, anyway)</p>

[ciaran_mcmenemy]

<p>admittedly it does seem quite grey, but I like the feel"</p>

[ciaran_mcmenemy]

<p>Like I have a picture and I can see the ground in detail but also clouds in the sky. Since I can see it, why can't I print it? (I'm a real amateur at this sort of stuff). I'm understanding that neg films have high d.r. (for mistakes and exposure correction after?) but printing redcues the d.r.<br>

oh, by double-negative, I meant slide film is actually negative too, you are basically getting a negative, bleaching it/re-exposing it, developing it again. I wonder if there are any other elements apart from silver that could be used in an emulsion?</p>