Tutorial: Illustrated Guide to B&W scan & processing

[buze]

I've made a small guide on how I scan & process my images. I think I describe a couple "tricks" that I haven't seen anywhere else, and I described my way of keeping the maximum quality while keeping the resource used reasonable.

The tutorial uses a 6x6 neg, but of course it is applicable to large format !

Hope you enjoy, feel free to comment.

http://oomz.net/bw_workflow/

[Frank R]

Thanks for posting this; I appreciate how long it takes to write and post these things.

I scanned through and read a bit. I have it bookmarked for later reference.

[Saulius]

Thanks for posting it and sharing your knowledge. When I get some time I will give your workflow a try and see how it works for me. I'm still digesting all that you wrote but right now just a couple questions.
You say to scan as a JPEG at 8 bit instead of as a TIFF format at 16 bit. Is your recommendation only to make the file size smaller? Smaller files are easier to work with but what about a loss of quality in the image. It's my understanding that with 16 bit images you will have more tones which gives you more room to make tonal adjustments which also helps lessen the chance of posterization. Also it's my understanding that saving scanned files in Photoshop format is best, then TIFF. These are lossless formats while JPEG loses info when compressing files which can also lead to digital artifacts. What's your thoughts on this? If you or anyone else thinks my assumptions are wrong by all means please explain why as I am no expert and am always trying to learn more.

I will have to try your technique of scanning at 4800 dpi and then downsize to 2400. In my own tests with my scanner I've found that I lose a lot of sharpness to the image by scanning at 4800. My scanner produces the sharpest scans at 2100 dpi. I'm not sure if I'll have significantly less noise doing it that way to make it worth my while for losing so much sharpness. I also have the software program SilverFast which allows me to do multisampling which in effect does what your method does. I can scan at my sharpest dpi of 2100 and if need be multi scan 2,4 8 or 16 times to help illiminate noise. But again there is a loss of sharpness and that sharpness is a big reason why I shoot large format. Have you used Silver Fast mulit sampling, any thoughts on this?

Again thanks for your efforts and please don't take my questions the wrong way. I'm just looking for the best methods to scan and work my images so I do appreciate your sharing your knowledge. All the best.

[Saulius]

Ok I guess I got ahead of myself. After some closer reading I see you later in your workflow convert the image from 8 bits to 16 bits. Sorry, but I did say I was still digesting the info. However I'm not too familiar with regards to converting from 8 bit to 16 bits. Is it not better to scan at 16 bits at the offset instead of converting later on?
Ok, I'll stop asking questions now until I've actually tried out your method, after further reading it does sound promising.

[buze]

Thank you for your comments,

Just realize that we will be using FOUR times 8 bits from the original image at 4800dpi to make the final 2400dpi 16 bit image.
Not only that, but we will be have 1/4 of the noise level since we are blending 4 values that are very close together.
This system is far superior than doing a 4 * "multiscan" of the same area, since the film can moves when being scanned (lamp heat); so all you do when you "multiscan" is risking a softer scan, for less noise.

Also remember that photoshop "16 bits" is only "15 bits" in real life, so all in all it makes the difference of precision from the source file a lot less than it appears, in fact, in my experience, I end up with better gradation AND a lot less noise by doing this downsampling than by using "native" 16 bits/TIFF.

JPEG high quality (the maximum quality setting) has virtualy no artifacts to speak of (In the EPSON software, it is not true for VueScan that is pretty lame in that regard), and since the image is going to be processed AND resized such artifacts are --in my experience-- irrelevant and invisible in the resulting image.

/if/ I could use JPEG2000 16 bits, I would; but I would rather use high quality JPEG than waste my disk space with TIFF files.

Also remember that to see any artifact in a print of a file that size, you would have to use a pretty good loupe and look at a 20x20 inches print with it...

The idea of using "4800dpi" is just to be able to oversample by a factor of 2 from the resolution you want at the end; these values would be different from different scanners I'm sure...

Hope this help...

[Ken Lee]

Really nice.

Hail to the folders from the 1950's ! ( I have a 6x6 and 6x9... love'm)

Hail to Windsor, and to England in general. Heavenly for photography.

[Larry Gebhardt]

Saving in JPG to startwith doesn't buy you anything besides a reduction of disk space used. Once opened into photoshop the image dimensions are what determine memory requirements. If you eventually delete the initial scan then I see no need to bother with JPG.

I am not a digital math expert, but as I understand it:
Scanning in 16bit mode will give you better highlights (since you are coming from a negative), even with your averaging technique. The reason being that in the initial scan at 8bits the highest zones your higlights (shadows in the neg) use are allocated relatively few tonal values. I suspect that your 4 pixel averaging won't overcome the major rounding that will happen.

On an asthetic issue I think your image could use a strong curve adjustment on the order of input 189 output 144. Of course this is just for my taste, and if you like your image a bit flatter that is fine. However, I think this may show up some problems in the highlights with your tecniques.

[Ed Richards]

> (In the EPSON software, it is not true for VueScan that is pretty lame in that regard),

If you are scanning with the Epson software, you are not getting all of the dynamic range out of your negative, which would explain why you do not see any benefit to 16 bit scans (really 12 bit). You get much better dynamic range with Vuescan or Silverfast, and staying at 16 bit through editing. The oversampling is a good idea, and what I use, but Silverfast's multisampling with alignment works most of the time.

[David Luttmann]

Ok. Where to start? First of all, converting from 8 bit to 16bit after the fact does nothing. Second, you'll notice the missing spikes in your levels....you are aware what that is, aren't you? I just finished playing around doing some comparisons working with 16 bit and 8 bit and I can tell you that it is noticable in the smoothness of sky tonality depending on how much in the way of adjustments you've made.

Third, converting to JPG saves you no time as when PS opens the JPG, it decompresses it and it becomes the same size as a TIF file. Thus, at the least, if you have a desire to stick with 8 bit files, you should at least use the TIF format. Sharpening files that use any JPG compression will show artifacts in photos with high contrast transition lines....such as the top of a forest joining the sky. As well, if you save the master scan as a JPG, and then save your completed worked-on file as a JPG....you are running the compression process a multiple of times. Sorry, but this is a no-no!

Your tutorial is well done....however, disk space is cheap. Stick with 16 bit to start and convert to 8 bit later. There are enough problems with tonality in the EPson scanners that we don't need to throw away data to save on $.05 of hard drive space. And finally, don't use JPG as you storage format.

[Kirk Gittings]

I don't have time to dig into this now, but this is not a workflow I would recommend for high quality work for many of the reasons Ed and David stated above.