Scanning of 6x17cm trannies.

[Jason Hall]

I am fairly new to using LF panoramic and although I have been capturing some great images with the Fuji GX617 camera(Velvia RVP 50 &100),I am not sure of the best resolution to have scans made for eventual printing at around 100cmx40cm.
I have had some Imacon scans done which look reasonable-although colours are a bit lacklustre compared to the trannies on a lightbox,but the file sizes are 850mb+ which are difficult to manipulate in PS etc.The files are supplied as tiffs should I compress them into JPG and if so will I lose quality?.
The sharpness and clarity of these trannies is incredible when compared to my 'digital' captures and I really want advice on how to preserve this quality through to the final print,any advice would help in saving my last vestiges of sanity!.

[Nathan Potter]

Work backwards from the resolution you want on the 100 X 40 cm. final print. Generally digital prints appear to be high quality when outputted at 300 dpi. which is near the limit of eye resolution at arms length.

For your situation that would require a scan resolution of about 12,000 X 5000 pixels for the Velvia (60 Mp). That equates to roughly 100 l/mm or 50 lp/mm. (10um scan spot).

Well you can almost pull this off with an Epson V 750 scanner at 2400 spi but I think you'll do better by scanning with a 5 um spot at about 5000 real spi. But at 5000 spi you're stuck with a large file as you have discovered although it seems to me that should still be less than your 850 MB experience. Any compression will have an adverse effect when working on the reduced file size in Photoshop. To see what you can tolerate work on only a reduced section of the original, the manipulations will go much faster.

BTW there is a technique of performing adjustments on a lower resolution file in Photoshop and then, at the end of the process, applying those adjustments to the original high resolution file. I don't know about the limitations of doing this but I believe there are some on the forum that can direct you to a source.

Nate Potter, Austin TX.

[Lenny Eiger]

I am fairly new to using LF panoramic and although I have been capturing some great images with the Fuji GX617 camera(Velvia RVP 50 &100),I am not sure of the best resolution to have scans made for eventual printing at around 100cmx40cm.

The best resolution is gotten with a drum scanner. It will exceed what it possible on an Imacon... There are many down there...

I have had some Imacon scans done which look reasonable-although colours are a bit lacklustre compared to the trannies on a lightbox

You can do whatever you want in Photoshop, including lightening the image, adding contrast and saturation. Whether or not you get great scan has to do with the operator, preferably someone who has an understanding of what you are trying to accomplish. Nothing is going to compare to backlit film, certainly not a print, etc. However, you can get as much out of it as any process can with what you are trying to do...

but the file sizes are 850mb+ which are difficult to manipulate in PS etc.

This is a reality of the digital printing process and will only get worse as time goes on. Adding more RAM to your computer is probably the easiest thing you can do, in almost every case... When you say manipulate, I hope you mean using a curve or hue/saturation adjustment layer.... to adjust things.

The files are supplied as tiffs should I compress them into JPG and if so will I lose quality?.

You will absolutely lose by compressing. Don't do it! Safest thing to do is to save ones' files in .psb format, for anything over about 700 megs.

The sharpness and clarity of these trannies is incredible when compared to my 'digital' captures and I really want advice on how to preserve this quality through to the final print,any advice would help in saving my last vestiges of sanity!.

If sharpness is what you are looking for, find someone with a drum scanner to work with.

Lenny

[Jason Hall]

Thanks to all for the great advice here.I guess the bottom line is that if I want the quality I'll have to live with the big files.
Just a note on upgrading RAM as a part solution,I am still using a 32 bit system which I believe can only use 3gb ram regardless of how much I add to the system so a new 64 bit system may be the answer there although I have also been told about a 'ram drive' software solution recently which is interesting.Anybody have any experience with this technique?.
Thanks again.JH.

[Lachlan 717]

Jason,

Don't get caught up in how it looks up close; a 100x40cm image will need to be seen from back further.

My suggestion is to try these at different resolutions on your screen.

If you're using Photoshop, set your canvas size to your end print size (100x40). Move to a part of the frame that has good detail. Set your DPI to, say, 300, and then move back from your computer to an approximate distance a person viewing the framed print would be.

Then try it at 150dpi.

If you can see a difference, go with the higher DPI. If not, then you're good to go with the lower DPI (i.e. more manageable file size).

Obviously, you can do this at other resolutions until you find the cut-off point. You will probably encounter diminishing returns at some point.

Don't forget that many, many people are wowed by an image from an iPhone. Seeing a good image at reasonable resolution on a big canvas will amaze them, regardless of 150dpi v300dpi...

[Jason Hall]

Thanks Lachlan,
thats a great idea and very helpful! much appreciated.I am just crazy about fine detail in my prints and to me anything without the sharpest fine detail is a waste of time and effort-thats just me I guess,but it drives me nuts trying to achieve ultimate quality and it is frustrating having to have scans made with so many variables including the scanner operator.
The suggestions posted here are a big help in understanding what is required to achieve the transformation from 6x17 transparency to print without compromising too much of the original image quality.Thanks all.JH.

[Lenny Eiger]

I wouldn't size down the file.... at least not the original one with all the masks and layers... if you ever size up you can use your adjustments.

Lenny

[onnect17]

Jason,
First, you're lucky this thread is still running. Many here in the forum consider the 6x17 format an outsider so I hope you’re able to read it before somebody starts complaining to the moderators.
I had some 6x17s printed on canvas and you could push it as far as 300cm X 100cm, zero sharpening. Now, you will need extra memory with any scan over 2000dpi. You should think in resolving that first (of course, the PC way is a lot cheaper)
Avoid any resizing in Photoshop. It just sucks, period. The only app with a decent interpolation I know of is Qimage, at printing time.
The light source in the drum scanner does not help with the colors. Separated channels in drums and LEDs are better.
100cm X 40cm is not much, so I think the Imacon at 3200dpi native should be enough. Keep it tiff at 16 bits.

[Jason Hall]

I wasn't sure whether 6x17 was classified as LF or not but being as it uses a Fujinon EBC LF lens I figured it may just scrape in.I wish I had the guts and determination to use an 8x10 field camera really but physical limitations do not permit me to unfortunately.Thanks again guys.JH.CHEERS!.