Scanning color negatives - best resolution?

[PeterAit]

I am scanning some 35mm Kodacolor negs using an Epson V750. Is 1200 DPI a good scanner setting to use? I am trying to balance detail extraction with scanning speed. ANy other tips would be welcome - I am totally new to this.

[Mark D Segal]

The resolution setting will not affect detail extraction unless you make it high enough that pixels are being invented (i.e. exceeds the CCD resolution of the scanner), or too low relative to the size of print you want to make. This question cannot be answered specifically without knowing what size you intend to print and what size is your media.

[PeterAit]

The resolution setting will not affect detail extraction unless you make it high enough that pixels are being invented (i.e. exceeds the CCD resolution of the scanner), or too low relative to the size of print you want to make. This question cannot be answered specifically without knowing what size you intend to print and what size is your media.

I don't agree with what you say. If I scan at too low a resolution, won't there be detail in the negative that is not captured in the scan? I don't want to "invent pixels," of course, but I also don't want to leave real pixels behind!

The point is, if I scan at the scanner's highest optical resolution (not interpolated resolution), I will get all the detail but the scans will be slow and the files huge.

[Mark D Segal]

If you chose to answers the questions I asked you I can answer your question about the appropriate resolution. I've been doing this stuff since 1999.

[Mark D Segal]

I don't agree with what you say. If I scan at too low a resolution, won't there be detail in the negative that is not captured in the scan? I don't want to "invent pixels," of course, but I also don't want to leave real pixels behind!

The point is, if I scan at the scanner's highest optical resolution (not interpolated resolution), I will get all the detail but the scans will be slow and the files huge.

Peter - the input resolution should relate to the output resolution and the size of the output. At the output end, the most often cited norm for human visual resolving power is about 300 PPI. So you need the number of input pixels to achieve roughly this output criterion. If you are printing from an Epson professional printer, the usual resolution of the print head is 360PPI (Canon is 300), so if you aim for 360PPI at output, once you know the output dimensions you can derive the input PPI. You will NOT leave detail on the table scanning at an input resolution that is appropriate to the maximum output dimensions you intend to print. I have tested this every which way from Sunday and I can confirm that you do not need to scan at the maximum optical resolution of the scanner, take all that time and end up with SUCH huge files. It's not necessary. (Some people claim that when you then go to downsize it helps clean-up artifacts - I prefer more directly controllable ways of doing this.) You will not leave useful information on the table scanning at the appropriate input resolution. If you are scanning media measuring 1.4 inches by 0.95 inches (35mm), and if you want to print the long side at say 17 inches, the total number of linear output pixels you need for that is 360*17 = 6120 pixels. Your original media long side is 1.4 inches. Therefore the total input pixels per inch you need at the scan stage is 6120/1.4 = 4371. Check: 4371 pixels/inch * 1.4 inches = 6120 total pixels, which divided by 360 PPI output gives you the 17 inches you want to print at that resolution. The formula for right-sizing the input pixel requirements per inch is [print length*output resolution per inch]/media length. If you are printing smaller the input resolution requirement goes down accordingly.You can of course experiment with whatever settings you want to try that deviate from this approach and you'll see what I mean.

[PeterAit]

If you chose to answers the questions I asked you I can answer your question about the appropriate resolution. I've been doing this stuff since 1999.

Who says I want to print? Anyway, that is totally irrelevant to my question--getting the maximum detail from these negs. Look, if you don't know the answer to my question, fine. Then don't answer.

[framah]

Being "totally new at this" SHOULD  make you want to work WITH an expert, not act like a jack ass. 

How about pulling your panties back out of your crack and be a bit nicer to one of the smart ones on here. All he is trying to do is help and you act like you already know more than he does even tho you are  "totally new at this".

Information like what you intend to do with the file is quite helpful and when the vast majority of people who scan negatives or slides makes prints from them, the usual assumption is just that.

Now, how about you start over and provide more info and be nicer. Who knows, you might even learn something ... seeing as how you are totally new at this.

[AFairley]

Jeez, talk about "no good deed goes unpunished"....

Here's a related V750 question for Mark, and I promise not to attack him for trying to help....

Say I want to use my V750 to scan chromes for a target Epson print size of 17x25 (I don't, but let's just say).  My target resolution for a 360 dpi print is 6120 ppi. The Epson's film scanning resolution is spec'd at 6400, but the effective measured resolution is closer to 2300 ppi (http://www.filmscanner.info/en/EpsonPerfectionV750Pro.html).  So should I set my scanning resolution to 6400 or to 2400?  Is the effective measured resolution I obtain with a 2400 ppi setting going to be actually much less?

[Mark D Segal]

Who says I want to print? Anyway, that is totally irrelevant to my question--getting the maximum detail from these negs. Look, if you don't know the answer to my question, fine. Then don't answer.

There is no answer to your question based on the information you provided when you asked it. The safest answer I can give you if you don't know or don't want to say what you will do with these scans is to scan at the maximum optical resolution of the scanner and suffer the time and file sizes involves.

[Mark D Segal]

Jeez, talk about "no good deed goes unpunished"....

Here's a related V750 question for Mark, and I promise not to attack him for trying to help....

Say I want to use my V750 to scan chromes for a target Epson print size of 17x25 (I don't, but let's just say).  My target resolution for a 360 dpi print is 6120 ppi. The Epson's film scanning resolution is spec'd at 6400, but the effective measured resolution is closer to 2300 ppi (http://www.filmscanner.info/en/EpsonPerfectionV750Pro.html).  So should I set my scanning resolution to 6400 or to 2400?  Is the effective measured resolution I obtain with a 2400 ppi setting going to be actually much less?

Hi Alan,

OK - now it gets interesting. I'll be addressing all this in some detail in my forthcoming review of the Epson V850 Pro, and don't worry, I'm not concerned about the attacks. Anyone who doesn't believe me is always free to do all the testing I've done and they'll see for themselves - each to his/her own. So let's go:

The number Patrick Wagner (Scandig) reports is a visually assessed resolving power of the whole scanning system determined with the aid of the line-pairs in the SilverFast USAF 1951 target. (The resolution number the scanner manufacturers give is an ISO compliant value based on the CCD structure - very different things.) I use the same target. It's a good target with one big limitation: it tells you what's happening at the center of the image, but not at the corners. Corner resolution could be worse. Anyhow, I haven't seen any different resolution target for measuring scanners, so that's what a number of us who do this work are using. The other thing about it, which is not the target's fault, because I've examined this target under a 30X microscope and I can confirm it is printed very well even at the finest detail (Group 7 Element 6), is the user's judgment when you try to look for white/black separations between the bars in the elements. You reach a point where they become fuzzy but are still somewhat distinct, and that status can persist over a couple of such blocs, each relating to a different resolution result. So what to do? I've landed on the idea that it's best to use a credible range rather than a point estimate that could be argued either this way or that way. But it's not a large range, so grosso-modo, without being too anal about it, one gets a useful answer.(And by the way, Patrick's eyesight and mine aren't quite the same - or his scanner is different - but I get better from the Epson V750 than he reports - not hugely, but better.

OK, how to interpret this information: what it means is that no matter how many PPI you scan-in, the perceived clarity of the image will not exceed the equivalent of what that target reading indicates. But you still need enough output pixels to optimize what comes out of your printer, otherwise you will be introducing yet another limitation on perceived end-point sharpness. So the arithmetic I provided in a post above remains valid up to the ISO definition of the scanner's input resolution (6400 in the case of the V750), and you would need all that resolution if you intend to make a 17.8 inch print at 360 PPI without resampling. Just know, however that in doing so, the "equivalent sharpness" if I can put it that way, is what the USAF target says it is. Now, the saving grace is that if you look at a 17.8 inch print from the viewing distance it would normally need (i.e. you are not pixel peeping - but enjoying the print), the apparent definition may well look OK, depending on the quality of the media to begin with. From my experience that is usually the most critical constraint on apparent sharpness - the quality of what we start with.

So bottom line: don't worry about the 2300 or whatever - that's the scanner and you have no control over it. For deciding the appropriate input PPI, use the arithmetic relating linear dimensions with PPI at input and output.

[AFairley]

But you still need enough output pixels to optimize what comes out of your printer, otherwise you will be introducing yet another limitation on perceived end-point sharpness.

Oh, right!  Thanks.

[Alan Klein]

Peter's asking a perfectly reasonable question.  It has nothing to do with what he wants to do with it after it's scanned.  You want to scan ONCE and be done with it.  Then you remove spots and adjust in post, ONCE.  Then you can decide whether to print 8x10  16x20 or just reduce for a small image on the internet.  Why would you want to scan and spot and edit separately for each final use?  Doesn't make sense;  waste of time.  So you want to get the max out of it on the first scan.    PPI  DPI etc is superfluous for the scan.

So Peter, I use the Epson V600 and scan at 2400, 48 bit.  The V700 might be slightly different.  Try different resolutions and see if you can tell if there's any difference.  I don't use ICE so the scan takes about a minute per 35mm picture.  When I scan 6x7mm 120 medium format, the files are approx. 200mb files; 37mb files for 35mm color slides.    Good luck.

[Alan Klein]

Oh another suggestion.  Scan flat.  Do all your adjustments in post.  Again, that will eliminate wasting time on extra scans. Of course you probably have Vuescan or the other non Epson program (I use Epsonscan).  Those others do all the adjustments pre-scan.  Reading all the problem others have had, I wonder the advantage, if any.  Does the machine come with Epsonscan also?  I'd try it with both Epson and the other program and see what you like.  Also, using Epsonscan, you won't have to learn another processing program; just use PS or whatever afterwards.  Note that you'll get 90% of the correction just adjusting Levels (black and white points) after the scan.  Then use the other sliders to tweak.  It'll take some time getting use too.  So don't get frustrated. 

[Mark D Segal]

............ You want to scan ONCE and be done with it.  Then you remove spots and adjust in post, ONCE. 

You mean YOU want to scan once and be done with it.

But no-one is talking about scanning more than once. Most commonly, one knows in advance what one wants to do with the scan, does it once and doesn't look back. That can save a lot of time and disk space. If one is a professional re-purposing the same images for all kinds of different unpredictable output situations - I agree - it makes most sense to scan at the optical resolution of the scanner and have lots of storage available. Otherwise it is not necessarily optimal. As for dust and scratch removal - doing this in post is slow and inefficient. One is best off using SilverFast's iSRD function for this at the scan stage. Saves scads of time, has refined controls (unlike ICE) and works very well, especially with a scanner such as the Epson V750 which has an infrared channel for detection.iSRD also works on Kodachrome, and can even work on SOME B&W media, depending on the extent of residual silver halide.

[Alan Klein]

Mark:   The OP indicated he doesn't know yet what he wants to do with it.  So for him, scanning it at max optical resolution the scanner can do is best.  I'm glad you agree with that.  As far as disk space, he'll get 35mb tiff for each slide.  He could save if he saves in jpegs but it will only take 37gb to store 1000 35mm slides in tiff.  That's nothing for most hard drives today with TB capacity.  Anyway, he'll probably blow his brains out by the time he scans 1000 slides, so it won't matter.   One question you can answer, what's the most real optical resolution can you get from a V750?  I'm not familiar with that model.  Do you have any figures on the V600?  I use 2400.

ICE is good but it increases the time it takes to scan.  You still have to go back and check and spot some anyway.  That's something Pete can try both ways to see what works for him the best. 

Regarding your recommending Silverfast, I think it's incumbent for the purposes of disclosure that you mention that you published and sell a book on using Silverfast and have an interest in it's success.    I never used it and it could be the greatest.  But I haven't been convinced to make the switch by what others have posted about it.  Seems to be very difficult to set up the parameters to get the scan right.  And then you have to scan again if it isn't right.  That doesn't happen with Epsonscan if you scan flat without any edits during the scan process. Again, that's something that Pete can try both ways since he should have both programs with his scanner.

[Alan Klein]

If he finds Silverfast is the way to go, I'm sure your book would be very helpful to him.

[Mark D Segal]

Mark:   The OP indicated he doesn't know yet what he wants to do with it.  So for him, scanning it at max optical resolution the scanner can do is best.  I'm glad you agree with that.  As far as disk space, he'll get 35mb tiff for each slide.  He could save if he saves in jpegs but it will only take 37gb to store 1000 35mm slides in tiff.  That's nothing for most hard drives today with TB capacity.  Anyway, he'll probably blow his brains out by the time he scans 1000 slides, so it won't matter.   One question you can answer, what's the most real optical resolution can you get from a V750?  I'm not familiar with that model.  Do you have any figures on the V600?  I use 2400.

ICE is good but it increases the time it takes to scan.  You still have to go back and check and spot some anyway.  That's something Pete can try both ways to see what works for him the best. 

Regarding your recommending Silverfast, I think it's incumbent for the purposes of disclosure that you mention that you published and sell a book on using Silverfast and have an interest in it's success.    I never used it and it could be the greatest.  But I haven't been convinced to make the switch by what others have posted about it.  Seems to be very difficult to set up the parameters to get the scan right.  And then you have to scan again if it isn't right.  That doesn't happen with Epsonscan if you scan flat without any edits during the scan process. Again, that's something that Pete can try both ways since he should have both programs with his scanner.

Alan, just a few factual points:

In his question, the OP did not say anything about purpose and he didn't say he doesn't know what he wants to do with the scans - that's why I asked, because unless you go for maximum CCD resolution, purposes matters to the answer he wanted.

Re the questions you asked me: the CCD resolution of the scanner according to the ISO standard with which it complies is 6400 PPI. This does not tell the story about either the resolving power of the scanning system, or the settings you should use. See my reply to Alan Fairley on all that, just above. I do not know what the ISO standard resolution of a V600 is because I don't have that scanner and never used it. The best way to decide what input resolution you should use for your purposes it to make tests, print the results and compare.

There is no secret I wrote a book about scanning with SilverFast 8. It was publicly announced on this website. I have no commercial interest in LaserSoft Imaging, they can sell as many or as few copies of their software as the market determines and it has zero impact on me. Trust me Alan, you can ask any author with the possible exception of Scott Kelby - you don't get rich writing such books - especially on a topic as arcane as this one with the limited residual market there is for the technology altogether. Selling a few books more or less passes under the radar - way under. I feel blessed and fortunate that I need not even think of depending on this stuff to put food on the table.

Not to put too fine a point on it - but I'm actually quite agnostic about software - for me, it's whatever works best in a systematic workflow for getting quality and efficiency. iSRD, as an example, happens to be a really good tool. It does not slow down scanning and from my experience with it, I'd say it eliminates just about all the crap you need to eliminate without impairing the image one iota. There can be "outliers" it doesn't pick up and those one deals with in LR or PS. Not to toot my horn inordinately, but a major emphasis of my book is about integrated workflows that combine SilverFast with Lightroom and/or Photoshop. Each of these applications have their strengths, weaknesses and optima, so after a great deal of research I've shown how many ways there are to skin this cat (and there could well be more, who knows). There are no pat answers - just different ways of doing things that have their pros and cons. This happens to be one particular area where dogma should take a back seat.

Finally, the nice thing about all this software is that the companies allow us to download and demo them. I encourage anyone who asks me to do just that - its free except for the time it takes to install, learn and play, see what floats your boat. Above all, I discourage being overly influenced by other peoples' problems on the internet. Remember Dragnet in the old days - 8 million souls, 8 million stories.........

Cheers

[Alan Klein]

Speaking of getting rid of spots, LR5 has a neat feature.  When you click on Spot Removal, you can check a box on the bottom bar that allows spots to "jump out" so you can easily find them to get rid of.  The new Spot removal tool also allows you to drag the tool if the the spot is elongated so the replacement will match exactly.  It doesn;t only have to be a spot.

[AFairley]

Back to the OP, seems to me he should alternatively scan for the largest conceivable output size he can foresee (8x10, 20x24, ?x?) or at the maximum rather scanner is capable of.  If the OP searches some of the drum scanning threads here, he will find some intense discussion what resolution is required for a scan that captures all the information film contains.  If I recall correctly, that figure was comfortably above what the V750 is capable of.

[Mark D Segal]

Drum scanning is a different proposition altogether. Given that the OP has an Epson V750 I think he should experiment with several resolution settings using his own media and see for himself what difference it will make to the output he wants. Doing one's own research and experimentation, especially when it is so easy, is the best way of being satisfied about what works best relative to the need. I'll end-up on this thread by also hinting that one needs to consider how much can actually be pulled off a piece of Kodacolor - have a look at papers by Tim Vitale and others about the effective resolution of these materials. It's a complex topic on its own as the chemistry has several aspects (silver particles, dye particles, clumps etc.) that influence resolvable detail in different ways, and then there is the quality of the original capture - camera, lens, exposure technique, steadiness etc. etc. The media itself is often the critical variable and when that's the case scanning in more pixels than of benefit to the resolvable detail in the media won't do any harm, but it's just a waste of time and storage - yes storage is cheap, but time has real value - at least to me; bottom line: do the research with your own stuff and decide what you like best.