88Mb file for A1 prints

[pete2]

Hi everyone,
I'm new to the forum and I'm deperate to find some infomation. How do I take a photo 88Mb file at 200dpi to make A1 prints of my paintings. I have been photographing my paintings in RAW in a Panasonic LX2. This gives me a dng file of approx 20mb but when I convert it to jpeg to send to the printers it results in a file of about 4mb. What equipment do I need to make such a large file.
Thanks, Pete

[teaking]

Could I ask a few question to try to help us help you

First of all why are you trying to create such a large file for example 88mb? is that something that has been asked for, as a jpeg should be smaller than the dng.

Also what are the pixel dimensions of your image? as you can work out what the dpi/ppi will be at A1 size from there you can make some decisions on how best to approach the printing.

For example when your editing has been finished you could apply output sharpening at the end for print which usualy makes it seem over sharpenedon your screen but can make all the difference in print, also you may consider adding noise to your image if you have enlarged it... sounds stupid but our eyes prefer texture and this gives the impression of the image being sharper rather than blurry and smooth that can happen when enlarged.

As for the tools you will need, an image editor photoshop, gimp, paint.net, paintshop etc etc and a printer or print lab facility.

[dcclark]

Do you mean "MegaPIXELS", not "MegaBYTES"?

Megabytes are used for the amount of space that a file (any file, not just images) take up on disk. Megapixels refers to the number of pixels in a file. The two numbers are not the same, although they may be related.

[pete2]

The original painting is far bigger but I have been told to print A1 at 200dpi, I need an image 4646px 6614px 87.9Mb. if this is so I believe the only way of getting it is with a digital back but this is far to expensive. I was wondering if I have any other option, maybe photographing in 35mm and then negative scanning??

[Vagebond]

Originally Posted by pete2

The original painting is far bigger but I have been told to print A1 at 200dpi, I need an image 4646px 6614px 87.9Mb. if this is so I believe the only way of getting it is with a digital back but this is far to expensive. I was wondering if I have any other option, maybe photographing in 35mm and then negative scanning??

It's been done before according to this forum. The last post in the thread does the arithmetic. By the way, the photographer used slide film.

If it works it still doesn't explain the 87.9Mb (Mb or MB ?) for a ±31 megapixel image.

[teaking]

So you need an image dimension of 4646px 6614px for a 200dpi print at A1, what is the dimension of the images you have taken in pixels? so we can compare the two.

Then we can determine how much the image needs to be enlarged, for example if the image you have now would print at 150dpi at A1 then I wouldnt bother enlarging.

You can scan a negative or your picture but you would need to do so at a high optical resolution and then upscale... I think thats how its done??

Other methods include step interpolation where you increase the image in size by 10% increments untill you reach the size you need. Then you need to sharpen the image and maybe add noise/grain

But it all depends on what you have now in terms of image.

[pete2]

Firstly, thanks for your help

The largest image I can take on my camara(panasonic dmc-lx2) is 3648 x 2736 which is far to small, I don't want to enlarge as I will loss quality. What my question is what is the cheapest way I can obtain a good quality image large enough to print approx A1. I know I could go to a professional photographer but as I produce 30+ paintings a year this would get very expensive and I cannot afford a digital back, large or medium format digital camara, so I am looking for a more affordable way to achieve this

[dcclark]

I don't think you could find a camera that can take such large images, at least all in one shot (there IS a 88+ megapixel camera out there, but it's $30,000+!).

You should realize that, if printing at such large sizes, you don't NEED 200 dpi. People will be viewing your whole painting, not smelling it -- they'll stand far enough back that they won't be able to see minor details that you'd lose at 100 dpi.

However, you could also take several photos (one of each quadrant of the painting, for example) and "stitch" them together like a panorama. This would require some care to get it done perfectly, but it would create a much larger image.

[pete2]

That's a good suggestion, I can try that. Thanks

[pete2]

Well done dcclark, I think you cracked it. I downloaded a stitching program took 8 quick photos and stitched them together. I think it needs a little practice to get it pefect but I think it might work.
Thanks again