Technical scanning questions

[noblebeast]

Hi everybody!

To get right to it: I'm shooting some medium format transparencies (color) that will be used in ads on large 6X4ft posters at bus shelters. I will be scanning them with an Epson 4490. The bus company has told my client only that the images need to be "as high resolution as possible." I did some searching around the internet for companies that print this type of poster and the only info I could find regarding the technicalities of image size was: 300dpi (of course) and that the image size of the file should be - depending on the company - no less than one quarter (some said one eighth) of the target image size on the poster. So if I'm understanding that correctly, if I give them an image file that on its own will print out to 18X12 inches, that would comfortably fill up the entire 6X4ft poster? To be more precise the photo image will not be taking up the entire poster, I just want to be sure I give them a large enough file so the posters don't show a bunch of pixelation and such.

Does anyone see what I'm getting at? If anyone here has experience with this sort of thing, I would be extremely grateful for any and all advice. This is my first foray into scanning for this type of work, and I can use any helpful hints or warnings anyone has to offer that have been gained through experience .

Thanks in advance,
Joe

 

[Doug Fisher]

You really need the bus company guy to give you the contact information for their output/printing service and talk to them directly. They will be able to help guide you because recommendations can vary from service to service. Remember that what is an acceptable resolution for a bus stop poster is usually quite a bit less than what is acceptable for a fine-art print.

Doug

 

[Mark Burley]

Last I heard the resolution was very low - roughly 64DPI at final size I think. Either way it is not that far above that. If however it is going to be back lit then the resolution is much higher.

You must insist on a technical guide/spec from the production studio. They are normally very helpful. If you don't get this from your rep then ask to speak to the studio manager. I have always found them to be very helpful.

Mark

 

[noblebeast]

Thanks for your replies. At this point, after much runaround via the phone (Oh you need to talk to this person; Who gave you this number? You need to talk to so-and-so; I have no idea, you need to call...[the first person I talked to] ), all that keeps getting reiterated to me is, "We can work with anything you give us, just make it as high resolution as possible." I'm thinking of handing them some 200mb files just to see how serious they are about the high res thing.

Thanks again!
Joe

 

[Ted Harris]

Joe, its your reputation going up on that poster .... as frustrating as it might be, see if you can get the accurate information. If the final size of the photo image is going to be ~ 12x18 then you will be performing on the very very outer limits of the capabilities of the 4990 with a MF tranny (you might want to try 4x5). To get the best results scan your tranny at 2400 spi then, after you have done all your image editing short of sharpening in Photoshop, go to "Image Size" and uncheck the resample image box and change the resolution to 300 dpi. Then recheck the resample image box and set the size to 12x18. Finally sharpen and you have the image to deliver.

 

[jd callow]

Joe,

You cannot do this properly with the epson.

You need a drum scan or at minimum an honest 4k per inch scan. A drum scan beyond 4k maynot be worth doing unless the film is a fine grained trany or a really fine grained neg. I've done many very large digital prints (reflective and backlit) and the proper resolution is or should be printer dependent. The printers I used needed around 300dpi or higher, but were ok at 200dpi. Six feet or 72 inches would mean that I would have wanted an image of 14k to 21k on the long edge. A 4k per inch scan would get you close to where you'd need to be.

Ted's method is the method I use. Fix density, adjust colour, contrast, make required edits, spot and then size to final print size w/o resampling. On a 4k scan this would give you a little better than 100ppi image. How you go from this to 200 or better is somewhat of a religious matter. Some will tell you stop there and others, myself included would recommend going higher in resolution. Those who would recommend enlarging split into multiple camps as to how to res-up the file. I'm not sure my technique is the best so I'll leave this step out.



The final thing to note is that you wil need to sharpen and that when you do do your final ready to print sharpening you will also need to spot one last time. Also worth noting is that different printers respond to sharpening differently. If you have the opportunity to run Mag tests I would certainly advise doing so.

 

[Ted Harris]

Joe, I was trying to be polite . IMO (although many will argue with us) JD is right and you really shouldn't do this with an Epson. You need to have your image scanned on a high-end drum or flatbed scanner and you can get that done for anywhere from $25 to over $200. The huge price difference is as much an indication of how various folks price scanning as it is of quality although at the low end you will not get much in the way of human interaction.

A bit of blatant self promotion ... I do scanning for others and send me a PM if you want to talk.

 

[noblebeast]

Thanks Ted and John. I should probably have made it more clear, but the images won't be as big as the final poster (and I have since been informed that the posters will not be as big as 6ft x 4ft), and they aren't going to be backlit. So I think I'm fine with the Epson - these aren't fine art prints or anything, just advertising posters for bus shelters, and the image will only be taking up a third to one half of the poster. At any rate, the printer is saying only 'give us the highest resolution images as possible, we can work with anything you give us.' How's that for precise instructions? And with six images needed, drum scans are getting too cost prohibitive for my client.

Joe

 

[lenny]

So I think I'm fine with the Epson - these aren't fine art prints or anything, just advertising posters for bus shelters, and the image will only be taking up a third to one half of the poster. At any rate, the printer is saying only 'give us the highest resolution images as possible, we can work with anything you give us.' How's that for precise instructions? And with six images needed, drum scans are getting too cost prohibitive for my client.
Joe

I want to be as nice as possible about this - I agree with the others - you are kidding yourself. An Epson is no match for a drum scanner. I also do drum scanning, and direct experience comparing results with one vs the other. It wasn't pretty.

Lenny

eigerstudios.com

 

[donbga]

I want to be as nice as possible about this - I agree with the others - you are kidding yourself. An Epson is no match for a drum scanner. I also do drum scanning, and direct experience comparing results with one vs the other. It wasn't pretty.

Lenny

eigerstudios.com

Which drum scanner do you use?

 

[lenny]

Which drum scanner do you use?

Don,

I use an Aztek Premier. It's an 8,000 dpi scanner, with an optical resolution of 8,000 dpi as well. It's quite a machine, a dream to use. Not for everyone, of course, as they are a bit expensive, but within the range of a professional scanning operation, which is what I do.

I also do museum quality printing - with a custom black and white ink setup, from inks I mix myself, on a 54 inch Roland. For color I have another 54 inch Roland dVinci system, 12 color, amazing wide gamut and very smooth prints...

I have some great tools, now I just need a few more clients...

Regards,

Lenny
eigerstudios.com

 

[donbga]

Don,

I use an Aztek Premier. It's an 8,000 dpi scanner, with an optical resolution of 8,000 dpi as well. It's quite a machine, a dream to use. Not for everyone, of course, as they are a bit expensive, but within the range of a professional scanning operation, which is what I do.

I also do museum quality printing - with a custom black and white ink setup, from inks I mix myself, on a 54 inch Roland. For color I have another 54 inch Roland dVinci system, 12 color, amazing wide gamut and very smooth prints...

I have some great tools, now I just need a few more clients...

Regards,

Lenny
eigerstudios.com

Good luck with your scanning and printing services. The Aztek sounds quite capable. What is the largest film size you can handle?

I wouldn't mind picking up a drum scanner, but it would have to be an older used model.

Don

 

[lenny]

Good luck with your scanning and printing services. The Aztek sounds quite capable. What is the largest film size you can handle?

The Premier does up to 8x10 film....

I wouldn't mind picking up a drum scanner, but it would have to be an older used model.
Don

A lot of these work quite well.

Lenny