I’ve had some very large photos done in metallic at AdoramaPix. The closest description I can give you would be the prints look like they’ve been put onto an auto body. That is to say they have the same look as auto body paint. It looks extremely good with the right type of material, a car for example. Generally things like inanimate objects would be good but probably not so good for things like landscapes and portraits.
I would recommend that anytime you’re using a new paper that you’re not familiar with that you start with a small file and order a small print. This way you can check to see that you’re getting what you want. Changes can be made much less expensively, then when you are satisfied you can go to the larger sizes.
This is an example of a photo I did as a large metallic print.
https://www.flickr.com/photos/dazt/3061616016/in/album-72157632619340092/lightbox/
The base photo was 3881 X 3104 pixels printed at 29” X 23”. That comes out to approximately 133-134 dpi.
You would normally want your prints to ideally come out at 300 dpi or better. Some photo printers won’t take anything less than 240 dpi or 180 dpi. Even if the photo printer will take some arbitrary lower number you will want to provide them with a print that is ideally 300 dpi. What this means is if your photo will have a base resolution of less than 300 dpi that you should do the upscaling and not the photo printer. This would be the final file that you would provide to the photo printer.
You doing the upscaling allows you to have more control and to see more readily what the finished print can support. Not all photos need 300 dpi in order to look good. You can verify how the photo would look, one of ways is by looking at the upscaled version on your monitor. A more definitive test would be when you’re ordering your smaller test print that this test print is from a small portion of the photo that you have scaled up.
Using the 300 dpi rule your 2500 pixel photo should be able to be printed at about 8”. But this is only a general rule of thumb. Your photo could quite possibly support a much larger size but that is highly dependent on many other factors. For example something that is basically a seascape and clouds could almost be scaled to any size but something that has many small details might look terrible if scaled too large. Ultimately you as the artist will have to make the decision.
By starting with the smaller file sizes to do your test prints it will make it much easier to send these to the photo printer. You will need to look at what file formats your photo printer can take. You might also need to look at the file sizes that they can take. If you are generating a file that you intend to print at a very large size at 300 dpi this can generate an extremely large file. You may for the very large photo sizes need to compromise on the 300 dpi just to keep the file size down to something that is acceptable.
Some additional words on printing very large photos. As you have larger photos printed the price will of course go up with the photo sizes. But something that goes up even faster is the cost of matting and framing these photos. You may want to investigate the cost of getting your photos matted and framed in the style that you wish before you order your large photo prints. This way you can budget the entire costs. You might find it very annoying to of ordered a $50 print only to find that it could cost you $200 to $250 to get it matted and framed. Additionally large photos that have been matted and framed take up a large amount of wall space. It is not unusual for a photo on the wall that is been matted and framed to be between 2 inches to 8 inches longer on a side than the photo itself. You’ll need to take this into consideration when finding a home for your masterpiece.
DAZ