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Colour Negative Scanning, Vuescan and ColorPerfect

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Why bother with C41 Colour Negative Scanning? I think Andy Barton put it perfectly when he wrote “C41 film, when exposed correctly and processed properly, will always give you highlights that are under control and shadows that are detailed. It has a dynamic range way beyond E6 slide film and has a beautiful, slow tail in the highlight end of the histogram when compared to digital shots, which might as well have an on/off switch when it comes to blown highlights. No digital capture can compete to a properly exposed and processed C41 negative, scanned by someone who knows how to scan, with a suitable scanner.

If you can get it right (and it's worth persevering) there is nothing in the colour world that will touch C41 negative film for the complete picture.”

 

 

(N.B. This is just an opinion. Please don't turn this thread into a film vs digital debate – join one of the many threads elsewhere discussing this issue).

 

 

Why home scan? So that the pro lab doesn't over expose your images losing your shadows and burning out your highlights.

 

 

The following isn't intended to imply in any way that I'm an expert on scanning. I've been doing it for about a week! There is surprisingly little on the net on the subject of colour negative scanning and I hope that posts following in this thread will only provide further tips to successful scanning with further insights into the software mentioned.

 

 

This is what I've gleaned so far from here Better colour neg scanning with VueScan. | Urban Motion

here Flickr: Discussing VueScan lock exposure tutorial in I Shoot Film

here http://www.l-camera-forum.com/leica-forum/film-forum/136222-v700-vuescan-colour-management.html

here C F Systems Innovations in Sight and Sound - Photoshop plug-ins page

and here VueScan User's Guide

 

 

 

 

There are two essentials for good colour neg scanning:

1)well exposed negs (use an incident meter if possible).

2)Well developed negs (find out when lab changes chemicals).

 

 

I'm using the Epson V700, Vuescan Pro, ColorPerfect and Photoshop. If you have a different scanner vuescan may look slightly different but I'm sure all the information here will hold.

OVERVIEW

The overview of the process is this: Vuescan gets all the information from the negative which is passed to Photoshop still in negative form. We would convert to a positive in Photoshop but it isn't very good at it so we convert to a positive with the Photoshop plug-in ColorPerfect.

 

 

Vuescan Pro and the Linear Scan

 

 

For best results we need all the info from the negative, and we achieve that by a few steps in pre-scanning. ColorPerfect likes a “linear” scan. I'm not sure what one of those is but it seems it needs Gamma at “1” with no processing of the RAW data from the scanner prior to going into ColorPerfect. To facilitate this we set up Vuescan Pro so that it doesn't clip any info and doesn't apply any curves and we won't do any white balancing. I also read that ColorPerfect likes Adobe RGB so we'll have that as our output colour profile.

There is an excellent article here Creating linear scans / VueScan Professional - ColorNeg - Your RAW converter for negative scans which you should read. I haven't tried the colour brightness stuff at the bottom yet but you should see if it makes a difference to your scans especially if you have an old scanner.

 

 

Initial Vuescan Set up for linear scan

Switch the scanner on then open Vuescan Pro.

The tabs along the top of Vuescan are:

INPUT

CROP

FILTER

COLOR

OUTPUT

PREFS

 

 

 

 

1) INPUT TAB

 

The important bits here are

48 bits per pixel (ColorPerfect likes this)

Preview res your choice

Scan resolution is your choice but high res means bigger files.

Rotation and Mirror is related to the orientation of the preview/scan.

I don't know what multipage or skew are.

Auto save/auto print/auto repeat and scan from preview can be left as NONE as they relate to preview, I think, and just take up cache memory.

I'm not sure what number of samples is but it possibly helps reduce noise in dark areas of the negative.

AT THIS STAGE ONLY CHECK THE MULTIEXPOSURE BOX. Your scanner will probably do a couple of scans later in the scanning stage one at a higher intensity to bring out the detail in the dark bits of the negative.

 

 

 

 

2) CROP TAB

Crop size max to see all your frames

Multi crop off to allow us to concentrate on our “Reference Frame” to profile the film

Border and buffer off to stop any automation of cropping

Preview area max to give you a good overall image of all frames

 

 

3) FILTER TAB

All off for speed

 

 

4) COLOR TAB

Color balance none (because ColourPerfect likes it this way)

Curve low and Curve High This relates to an S curve of the levels/contrast curve. I've zeroed these as I believe ColorPerfect wants the info as untouched as possible. I must admit I don't know if it's better to do this. I think Julian Thompson leaves his at the default value of 0.25 and 0.75 respectively. See which you prefer.

 

 

BRIGHTNESS 1 (leaving this at “1” gives us our Linear Scan. I think “brightness” is vuescan's “Gamma”) THIS IS VERY IMPORTANT.

 

 

BRIGHTNESS RED/GREEN/BLUE if you have an older scanner read the bottom of this page ( Creating linear scans / VueScan Professional - ColorNeg - Your RAW converter for negative scans )

 

 

Also very important is leaving the NEGATIVE VENDOR AS GENERIC.

 

 

OUTPUT COLOUR SPACE Adobe RGB (because the writers of ColourPerfect say it likes it) but Julian Thompson recommends ProPhoto RGB so see which you prefer.

 

 

Raw Output With “scan” means that the TIFF is produced during the scan. Select this if you don't want processes such as ICE to be active. Raw Output With “save” means that the processes such as ICE can be completed before the TIFF is saved manually (by going to FILE>SAVE).

 

 

5) OUTPUT TAB

Here we can stipulate to where the file is saved.

If RAW FILE alone is selected you get a TIFF negative outputted. Don't tick both RAW FILE and RAW DNG format which results in a negative dng file out putted. The dng file would be opened by Camera RAW before going into photoshop so it wouldn't be a linear scan anymore.

 

 

At this stage we can goto FILE and save all these settings (SAVE OPTIONS) with an easy to recognize name like “Scanning for idiots”. We can “load” it when we come to start scanning next time.

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PROFILING THE COLOUR NEGATIVE

I would suggest that you sacrifice the second frame (the second frame so that the lab tech won't cut it out and throw it away) on each film to provide a “REFERENCE FRAME”. That is to say, after you've exposed your first frame on your film in-camera take another exposure with the lens cap on thus giving you a good area of unexposed film to be used to profile the film.

 

 

We start the scanning process with a PREVIEW.

Remember at this stage we've only ticked multi exposure on the Input tab.

Press the preview button (bottom left) for our first preview scan:

 

 

PREVIEW SCAN 1

Having selected no cropping, the whole of the flat bed will be scanned. Now manually crop down to the unexposed REFERENCE FRAME ensuring the lines of the crop lay well within the edges of the frame so that the scanner's exposure isn't mislead. (If you don't have a reference frame try to crop as close as possible to the unexposed interframe gap. Alternatively you may have had the film leader returned with your negatives – ask for it)

NOW TICK EXPOSURE LOCK AND PREVIEW AGAIN

 

 

 

 

PREVIEW SCAN 2

 

 

 

 

After this second preview LOCK FILM BASE option becomes available at the bottom of the INPUT TAB. Don't change or move the cropping. TICK LOCK FILM BASE THEN PREVIEW AGAIN.

 

 

PREVIEW SCAN 3

After this 3rd preview TICK LOCK FILM COLOUR THEN PREVIEW AGAIN.

 

So we have done 4 previews now. (Maybe this isn't needed? Perhaps you can inform us).

 

 

 

These are the only previews we need to do for this film. We have profiled the film and set our scanning exposure. Without changing any settings slide the selection over to any of the frames you want to scan. Alter the cropping as appropriate and just hit the SCAN button.

During the scan sequence the NEGATIVE RAW TIFF file is deposited in My Pictures or wherever you stipulated earlier.

 

 

Edited by Stealth3kpl

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PHOTOSHOP AND COLORPERFECT STAGE.

 

 

You may be wondering what real difference does it make whether one creates a Positive of the negative scan with Photoshop or with ColorPerfect. In this figure the image on the left is Photoshop's conversion, and the image on the right is ColorPerfect's version.

I'd like to point out that the algorithms of ColorPerfect seem much better than the old ColorNeg, and indeed the demo version of ColorPerfect. I find I really have to do very little to get an acceptable image with ColorPerfect proper.

Open the file in Photoshop. You should see the histogram has no clipping showing that all the information is in the file. Don't “INVERT” with Photoshop as the colours won't be very good. Instead we change our negative to a positive using the ColorPerfect plug-in found under filters.

Open ColorPerfect. Make sure it is in ColorNeg mode. You can stipulate the film profile at the bottom left. Top right, Julian Thompson suggests leaving Gamma C at 1.5 in most cases to avoid blowing highlights.

There is a drop-down menu with BLACK selected by default.

 

You can select any of these other headings and use the vertical slider just to their left to alter values to taste. So far I've only found I've needed to alter Gamma (acts as brightness) but this would be image dependent. If settings look ok press OK and it drops back into photoshop to be played with as normal.

A very useful looking article is here. Converting historic negatives - ColorNeg - Your RAW converter for negative scans

 

 

When a new film is to be scanned,”Release Memory” (Ctrl+Y) in viewscan and switch the scanner off to ensure no settings are saved.

 

 

This is very much a beginner's-get-started guide. I know little of any of the settings in the programs used. I'm hoping that members' subsequent posts will constructively explain how to get more out of these programs than we can with the foregoing. Perhaps someone could take the time to do a beginner's guide to ColorPerfect which I feel is the key to successful colour negative scanning.

Pete

 

 

Thanks to Julian Thompson, Andy Barton and to “nightfire" for suggesting ColorPerfect.

Edited by Stealth3kpl

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This is way to complicated.

 

I take the first frame with a range of colors, prescan, set exposure, set color balance, and save the settings. Each frame I then scan using the saved and recalled settings. There might be a small adjustment if the exposure is off a little or the lab chems are not right on. No program can set it all perfectly every time.

 

Konica Minolta 5400 & KM supplied software is all I use. Scan in manual mode.

 

This is really no different than what I used to do in my color darkroom when I made contact sheets from color neg. I just went back to the basic setting for print exposure and color balanceand made a 4x6 test of the contact print area. Adjust and go. I don`t make bad exposures.

 

All other changes are made in photoshop.

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This is way to complicated.

 

I take the first frame with a range of colors, prescan, set exposure, set color balance, and save the settings. Each frame I then scan using the saved and recalled settings. There might be a small adjustment if the exposure is off a little or the lab chems are not right on. No program can set it all perfectly every time.

And, of course, I've also tried this.

This thread is for those who'd like to use Vuescan Pro and ColorPerfect or would like to inform us how to use Vuescan and ColorPerfect effectively.

Cheers.

Pete

Edited by Stealth3kpl

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Indeed - I have to side with Pete here Toby. Colorperfect is an incredible piece of software and the process isn't complicated (it's just that Pete is giving a step by step which makes it look worse than it is!). The colours are so dramatically better than anything else I have ever tried that the first time I used it I actually gasped in amazment as I stared at the screen. It's THAT good.

 

PS - Pete - the only reason it is worth outputting to ProPhoto is that although you can later choose to discard some information and come down in gamut size to Adobe RGB you can't go UP to ProPhoto once you've committed the scan. So it's worth doing ProPhoto for your negative scan archives in case you later need that extra gamut.

 

Great post though, well done !

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PS

 

Forgot to mention - on the lock film base colour thing - I spoke with Ed Hamrick about this and you he reckons you don't need to worry about scanning the whole flatbed or about having a blank frame. He tells me that as long as the preview image you use has at least 5% of unexposed film this is sufficient to do the job. Hence I don't bother with this now and the scans seem fine. Also I actually create a preset for each film type I use to save me the hassle of re-setting this each time. Seems to work great.

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Hi Andy!

 

No, I was moaning to Ed actually, telling him that it was a PITA to try and adjust the crop to the gap between frames (if I'd not bothered to do a sacrificial shot as Pete mentions) and this was when he told me that you can select anything as long as there is at least 5% unexposed film.

 

So now I just choose a light frame with plenty of film base colour and use that - or if it's a dark roll I just grab a lump that includes a gap between frames. Seems to work fine, as Ed suggested.

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This is way to complicated.

 

I take the first frame with a range of colors, prescan, set exposure, set color balance, and save the settings.

All other changes are made in photoshop.

 

From post 3:

 

"In this figure the image on the left is Photoshop's conversion, and the image on the right is ColorPerfect's version."

 

 

My initial posts might look like a headache but once the settings are saved it's seconds to reload them. With the V700 each preview scan is very quick and doesn't take any brain power. Then you just move the selection around to the frames you want to scan. It's actually very quick.

I'm getting a little more used to ColorPerfect now. I'm setting the Gamma C on 2+51/256 and using the highlight stops range clip at the top (which seems to be highlight recovery) to avoid blowing highlights.

Any more tips let us all know.

Pete

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I hope you don't mind me coming back to add some further details of ColorPerfect (CP). The interface isn't intuitive to many people so this is a getting started guide to the ColorPerfect Enigma Machine.

 

As stated earlier in the thread, open CP in Photoshop via Filter>CFSystems>ColorPerfect.

 

 

When you image has opened check that, top right, you have selected ColorNeg and "L".

You'll have a positive in the preview window. Bottom left choose the film profile from the drop down boxes.

 

 

 

Set Gamma C at 2.2 for your negative tiff if it is ASSIGNED (not "converted" which would destroy color accuracy) with an Adobe RGB profile (2.5 and 2+51/256 are close enough too).

 

Set Gamma C to sRGB if assigned with an sRGB profile.

 

Your converted RAW TIFF (ie your positive) will probably look pretty good.

 

 

 

If you think the white balance looks off just left-click something mid grey until it looks good. If there is nothing to click then in the drop-down adjustment options choose "Autocolor" which is an adjustable estimate of whitebal. If this isn't working you likely have a poor scan but you may be able to remedy things using "Film Type". Look up the help page on how to use this.

 

 

 

At this point I look at highlight clipping middle top

 

 

 

 

 

Usually 0.2 or 0.5 is sufficient to stop your highlights burning out. I'm not certain of any benefit of altering 220. If you know, let us know too.

 

 

If the negative was well exposed this is probably all you need to do. I have noticed that if there is a lot of contrast in the image i.e. your subject is well exposed but there's alot of lowlights in the image, a better result can be gained by adjusting exposure using "Gamma" in the drop down adjustment options (labelled "Black" by default). Select Gamma and slide the vertical slider to taste.

 

 

I suspect that "Black" doesn't refer to blacks in the traditional sense of imaging software but refers to overall exposure. "Whites" seems to be related to contrast or milkiness/fogginess as the producers of CP call it.

 

 

That's more or less it. Click OK and take it back into Photoshop.

 

It isn't very user friendly at first sight but it's well worth persevering and once you get an inkling of what the buttons do it seems remarkably simple. There is very little to set up. If you feel you've made a bad click you can click back a step or two using the buttons top left, or the double chevron to take you back to the start (see fig1).

The zoom button is top left also.

In Fig1 top right you can see a initial>Previous button. If your last conversion was successful and your present file is a similar scene, pressing this brings the previous file's ColorPerfect settings into play. Pressing it again takes all adjustments away. Pressing one more time brings up the settings that were in play before you started pressing the button!

 

 

That's just about all I know about using ColorPerfect. If I make any major break-throughs I'll update this. I hope others will chip in to.

 

 

Pete

Edited by Stealth3kpl

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Really great Pete - interesting about the Gamma C altering the actual colours - I'd never noticed that before. It's fairly minimal on most of the scans I've played with and I won't be re-doing them all but certainly from now I'll use 2.2 for Adobe and SRGB for RGB, then alter the gamma to set the spacing.

 

Not so sure about doing white balance in CP though - I had a go at it and feel that the slider in aperture / LR is better.

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Colorperfect is incredibly obtuse in its interface. However, I do think it gives great conversions. After working through some of the math myself and playing around with a number of different conversion schemes, I've convinced myself that Colorperfect is one of the better ones. I also like the one I'm writing myself

 

I also think that setting the white balance in the inversion stage is pretty important, as is getting the right overall contrast. At least getting in the right neighborhood. While small tweaks work fine in Photoshop/Lightroom/etc. after inversion, large tweaks to those parameters really start to affect the color saturation.

 

As far as basic inverting goes, the author of Colorperfect has two very good points to make:

 

- Photoshop's gamma control in levels is broken for large changes in gamma (much over 1.4 or .71 if I recall). This is important because it's in the area of the gamma shift we need to make to go from a linear scan to one that is appropriate for negatives. It can be gotten around by making multiple smaller gamma changes until you reach the desired gamma. Or use a program that does it correctly.

 

- Photoshop's invert is not the proper way to invert negatives. Photoshop's invert essentially does:

newpixel = (1 - pixel value)

 

For inversion, we want to do:

newpixel = 1/pixel value

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Set Gamma C at 2.2 for your negative tiff if it is ASSIGNED (not "converted" which would destroy color accuracy) with an Adobe RGB profile (2.5 and 2+51/256 are close enough too).

 

Set Gamma C to sRGB if assigned with an sRGB profile.

 

Your converted RAW TIFF (ie your positive) will probably look pretty good.

 

Does the RAW scan coming out of Vuescan have a profile assigned by default? If so where is that set? I have simply been using the default gamma until now.

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Does the RAW scan coming out of Vuescan have a profile assigned by default? If so where is that set? I have simply been using the default gamma until now.

 

No, you'd have to set it in Photoshop or elsewhere. I'm pretty sure Vuescan doesn't attach a profile to RAW scans.

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No, you'd have to set it in Photoshop or elsewhere. I'm pretty sure Vuescan doesn't attach a profile to RAW scans.

 

So, should I be assigning a profile in PhotoShop before starting the plugin?

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If I recall correctly, assign a profile to the image before using the plugin or after using it gave the same results. I could be wrong though. Assigning upon opening is the easiest, since you can set Photoshop to ask if there is no profile.

 

sRGB and AdobeRGB are the obvious choices. And you want to 'assign' not 'convert to' just to be clear.

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Why bother with C41 Colour Negative Scanning? I think Andy Barton put it perfectly when he wrote “C41 film, when exposed correctly and processed properly, will always give you highlights that are under control and shadows that are detailed. It has a dynamic range way beyond E6 slide film and has a beautiful, slow tail in the highlight end of the histogram when compared to digital shots, which might as well have an on/off switch when it comes to blown highlights. No digital capture can compete to a properly exposed and processed C41 negative, scanned by someone who knows how to scan, with a suitable scanner.

If you can get it right (and it's worth persevering) there is nothing in the colour world that will touch C41 negative film for the complete picture.”.

 

I might have said this two years ago, but I have given up on C41 colour completely now. In fact, I gave away my last C41 colour negative film yesterday.

 

I know how to scan, but I have increasingly found that scanning C41 colour negative film to be a very frustrating experience. Whether it's just "me", a lack of decent labs, staffed with people who know what they are doing, stale chemicals, or what ever, I am sticking to black and white film in the M2/MP from now on.

Edited by andybarton

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I might have said this two years ago, but I have given up on C41 colour completely now. In fact, I gave away my last C41 colour negative film yesterday.

 

I know how to scan, but I have increasingly found that scanning C41 colour negative film to be a very frustrating experience. Whether it's just "me", a lack of decent labs, staffed with people who know what they are doing, stale chemicals, or what ever, I am sticking to black and white film in the M2/MP from now on.

 

Lately I have been tending to go the other way and enjoying using C41 (admittedly in my Rolleicord Vb). I had given up trying to scan colour negs years ago when I had an Epson Perfection 3200. A while back I bought a V700, never intending to use it for colour. However a very kind forum member gave me a stack of Kodak colour 120 rolls, so I have been working my way through them and having them developed (negs only) by AG Photo Lab. As written in the other scanning thread, I tried Vuescan and then SilverFast SE thinking these would be superior to the EpsonScan software, but the results were very disappointing. It was only when I used the Epson software (on it's default settings) that I got the kind of result I had been expecting. My film Leicas have been used exclusively for b&w with never any intention to use colour, but the results from the Rollei have given me pause for thought!

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I often feel that the larger 120 negative gives the software more to thinkabout giving a better result. I might be imagining it though. I now preview my 35mm scans on a high setting before scanning at the desired setting. I'm sure it helps.

Pete

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