Today’s Question: I’m a little confused. Many, if not most, professional photo labs request that you send them images in a JPEG format. If artifacts are an issue, why don’t they request images in a TIFF format?
Tim’s Quick Answer: In my view photo labs should not suggest using the JPEG file format for printing because of the risk of visible artifacts. They do so, I assume, because the JPEG format is widely supported and results in a small file size that is easy to transmit via the internet.
More Detail: In some ways you could say that photo labs request JPEG images because photo labs have always requested JPEG images, at least in the context of online submission of images. The JPEG format is very widely supported and yields smaller file sizes than other file formats. However, that smaller file size comes at a potential cost in terms of print quality. Therefore, for printing I suggest submitting images as a TIFF or PNG file.
To provide some context, I saved a 20-megapixel image as a TIFF file with ZIP (lossless) compression and the file size was 146MB. The same image saved as a PNG file with maximum (lossless) compression was 95MB in size. The same image saved as a JPEG image with maximum quality (but lossy compression) was only 12MB.
In my view the risk of visible artifacts is a very real concern whenever printing a photo, and especially when that print will be relatively large. I therefore strongly recommend not using JPEG files for photos that will be printed. With high-speed internet being relatively ubiquitous today, sending a file that is around 100MB rather than around 10MB is not a major inconvenience, and in my view well worth it when it comes to helping ensure optimal print quality.
If a printer only supports uploading images in the JPEG format, I suggest finding a different printer. For example, I have had very good results getting prints from Bay Photo (https://bayphoto.com), and they allow you to upload images in a wide variety of image formats, including TIFF.
