Shrink scan files in Photoshop?

[Mike Rawcs]

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I'm currently using a Minolta Scan Elite 5400 film scanner to scan colour negatives. At 16 bit setting I'm getting a 233 Mb file: great quality but not very Aperture / Lightroom friendly. I have no idea about which file size will give which size print but it makes sense to get the maximum quality, doesn't it?

 

I believe that it is possible to reduce a file's size in Photoshop. Anyone know how and what does it do to the quality of the scan?

 

Thanks,

 

Mike.

[Max Alfy]

Hi Mike,

 

The Elite 5400 is an excellent scanner which I use since a few years to convert all my slides & negatives to digital, a still ongoing project.

My experience is that for color negatives, there is no need to go to 5400 dpi: at 2700 it already resolves the grain of Reala 100 which was my favorite film. Scanning at 5400 and then downsizing to 2700 just adds a software step which can only degrade the signal. And the files are only 50 Mb instead of >200.

 

In my experience 5400 dpi is only useful for positive film such as Kodachrome 25 which has no grain.

 

Make a test: scan the same negative at 2700 and then at 5400, and observe them side by side at the same picture size, meaning the 2700 scan @ 100% and the 5400 @ 50%: they will look pretty identical in terms of grain and resolution. If you observe them both @ 100%, the only difference will be that the grains are twice as large on the 5400 scan.

 

So scanning at 2700 will not impair the size of the enlargements which can be printed. Note that this concerns only color negatives: the story will be different with K25 or special purpose high definition B&W films, and if you don’t resample down the scans thereafter.

 

To reduce resolution (and file size) in Photoshop: Go to Image/Image size.

In the dialog box: Check the box “Resample Image”, and in the drop down menu choose “Bicubic sharper (best for reduction)”, then just type in the desired resolution (e.g. 150 instead of 300): the pixel numbers are automatically divided by 2. Then press OK. This can be made into an action and used for batch processing of course.

 

Hope this will be useful,

[wparsonsgisnet]

Mike, as I recall (it's been a while), I was using VueScan as the interface to the 5400. I did get a big scan file. I took that into PS and modified it the way I wanted it and then deleted the scan file.

 

I still have the negative and regarded the scan file as an intermediate step.

[Mike Rawcs]

Thanks Max, Bill, this is the information that I require. I'm scanning today, so I will test at 2700. I can always re-scan the "greats" at full resolution if I want at a later date.

 

My current workflow is to make an initial pre-scan of a photograph and decide if it is worth continuing: some shots are experimental, shot from the hip etc. so if they totally miss the mark I save the negative, but don't scan. If all is o.k. I'll make a final scan. This is to ensure that I don't miss any "sleepers" the photographs that grow on you over time.

 

Then into Photoshop to remove any dust marks, scratches etc. then into Aperture to process the negative as I would in the darkroom. Next step is to make a contact print of the photographs scanned from the roll of film and store the negs and contact prints.

 

Thanks once again.

 

 

Mike.

[Max Alfy]

I agree with your workflow which is all right if you scan occasionally. But after a few tens of slides with the 5400 driver and Silverfast which was part of the package, I realized that I was loosing a lot of time with the previewing and pre-editing.

 

I therefore streamlined the workflow: I run the 5400 on my portable with every control set at default, meaning no levels/color adjustment, no crop, only dust removal remains (it is excellent). I just continuously feed the 5400 with film strips until the film is finished, then transfer the files to my desktop computer with a USB key.

 

On my desktop computer I run the files with PS. I made an “action” which adds a Background copy in order to choose sharpening, and Levels, Curves and Saturation layers. I run this as a batch on the whole film, and am then ready to start working: crop, orientation, initial sharpening, and all the color correction stuff (and discarding lousy shots). While doing so, I feed the 5400 with the next film’s strips…

[Mike Rawcs]

Max, that's not a bad idea! I have both I-mac and Macbook so I could do the same. With my abysmal knowledge of Photoshop (I've never even learned layers) I tend to just use Clone Stamp and healing brush to remove any dust spots and scratches and save, then use Lightroom or Aperture (can't decide which to stick with) to make non-destructive amendments to the photographs then Web and print (contact and, for the "specials", print.

 

I do find myself waiting for the scanner to complete before I can continue with the fun.

 

Do you use Lightroom / Aperture to keep track of your work?

 

Mike.

[Max Alfy]

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Sounds like a good workflow Mike.

 

I started scanning way before Lightroom was created, so my workflow is based on PS and Bridge, occasionally ACDSee to create self-exe slideshows. Capture One came free with the M8 three years ago, so I never used ACR.

 

Windows XP runs all of that. The best programs are the ones which are used and mastered!

[magd0328]

Mike,

I would say first make any large shifts in levels or curves that you want to make. ie keep the file in 16 bit mode for these changes to avoid posterization. Then change the file to 8 bit and save. As long as you don't make any further extreme levels or curve shifts you should be fine. That should immediately cut your file size in two.

[Mike Rawcs]

Thank you all for your advice: I've tried scanning at 2700 as Max suggested but when I come to spot I find the detail too small to easily rectify any defects (dust etc.). In Actual Pixels (Photoshop) the detail shown at 2700 is about one third of the image depth - at 5700 it only shows about one sixth, so the detail is much bigger (hope this makes sense).

 

I have also used Max's tip of scanning to Macbook then copying photos to I-Mac for Photoshop editing and found it a great timesaver.

 

Magd0328's advice sounds good but what will it do to print quality? All through my workflow I want to maintain the best image quality possible and would rather spend the time than lose it.

 

Mike.

[magd0328]

Mike, I don't think it will make any difference to print quality. It is highly likely that you will be sending an 8 bit file to your printer anyway. But don't take my word for it, print two identical pictures, first as a 16 bit file, then convert it to 8 bit and print it again. I'd be willing to wager a pint you won't be able to see the difference.