Printing from jpeg versus printing from Photoshop?

[TonyW]

I don't print many of my images but when I do I send to a local commercial lab. They accept high resolution and high quality jpeg files, Adobe or sRGB, which are normally quite good.

Occasionally though, there are images where I want good definition in light areas (clouds for example) or dark areas. The jpeg images sometimes show banding or posterisation where the Photoshop ones don't, presumably because of the higher bit depth.

In these cases, would it be better to print directly from Photoshop rather than export a jpeg file and print from that?

[george013]

I don't print many of my images but when I do I send to a local commercial lab. They accept high resolution and high quality jpeg files, Adobe or sRGB, which are normally quite good.

Occasionally though, there are images where I want good definition in light areas (clouds for example) or dark areas. The jpeg images sometimes show banding or posterisation where the Photoshop ones don't, presumably because of the higher bit depth.

In these cases, would it be better to print directly from Photoshop rather than export a jpeg file and print from that?

The first question you must ask your self is what do you compare? Where did you get that Adobe image from? Where do you view the jpg?

I can't help you further but these are the basic questions you've to ask your self.

George

[Shadowman]

Tony,

Are you asking from the labs point of view, if so the lab assumes you've done all the editing necessary prior to uploading the file; including correcting for banding, if the image you've uploaded looks like its low quality hopefully the lab will warn prior to them providing you with service ?

[DanK]

The jpeg images sometimes show banding or posterisation where the Photoshop ones don't, presumably because of the higher bit depth.

Are you shooting raw?

Do you see the posterization in the jpeg images you send to the lab, or just in the prints they return? I ask this in part because some labs let you specify whether they should print the file as is or modify it further (usually for WB).

Do you send them the largest size file you can, exported or saved at the highest quality?

In my experience, posterization usually occurs in the process of editing an image that started as a jpeg. It is also more likely if you are editing in 8-bit, regardless of the starting format. I rarely have a lab do my printing, but when I do, I always have them print with no further modifications, and I have never noticed posterization in the prints.

Not knowing any of the specifics, I think the answer to your question in the abstract is yes, not only because of avoiding data loss, but also because many printers can handle colors outside of the sRGB and aRGB gamut, so you may avoid some problems with out-of-gamut colors.

I'm somewhat lazy about printing, just in the interest of full disclosure, and print from Lightroom rather than Photoshop, even when I have edited an image in Photoshop. LR gives you less precise control--e.g. over output sharpening--but I find that it produces excellent prints, and the print module interface is for the most part excellent. E.g., it's easy to set up templates. I print a small number of cards, and I have two templates set up, one for landscape and the other for portrait, that size everything correctly and place my logo where it belongs, in the proper orientation.

[Manfred M]

Tony - this is not an easy question to answer because it depends to a large extent on the colour data that your camera captured through the way that you processed it to the printing process used as well as the paper and in the case of ink-jet printers, the colour set used by the printer; i.e. the gamut of the output process.

The workflow that one uses to produce the output image is equally important. First question - are you shooting raw or JPEG?

If you are shooting raw, then you are most likely dealing with 14-bit data that should be processed in Photoshop as 16-bit, using a wide-gamut colour space. My default working colour space is ProPhoto RGB (80% of visible colours) and I do know that some people default to AdobeRGB (60% of visible colours). As a rule of thumb, a wider-gamut colour space does have some advantages. The sRGB colour space reproduces around 35% of visible colours.

A JPEG output will be 8-bit, regardless of whether the camera is set to AdobeRGB or sRGB. AdobeRGB will theoretically be more prone to banding than sRGB.

Posterization comes about when there are not enough discrete colours available to show enough discrete colours for smooth transitions. The two main reasons this occurs is that the bit-depth being used is too small to reproduce the discrete colours or that the quality of the JPEG output is too low and the lossy compression algorithms do not create enough steps between the discrete colours.

Photoshop lets you output in many different formats, so I'm not quite sure what you mean here. If you are referring to the .PSD files, in what you have written? Most commercial printers do not accept these, so far as I know and the standard is usually a JPEG and sometimes a TIFF file. So far as I can determine, a the PSD format is likely a variant of a layered TIFF file.

When it comes to printing, even on the highest end ink-jet printer (with a dozen cartridges using a modern, up to date ink set) with the highest gloss paper, we are likely getting less than 1 million discrete colours being reproduced. Even the least expensive sRGB compliant computer screen can reproduce over 16 million distinct colours. The difference is that those colours cover a much smaller area of the human visual range (i.e. we will not be able to make out the difference between two adjacent shades). One does not need anything more than 8-bit output for even the best colour printers to produce accurate colours.

The question of why you are getting blocking when you send a JPEG to your commercial printer can likely be attributed to a few factors. Have you asked for the ICC profiles of the printer and paper combination that is used? If you have that, you can soft-proof your work and have a reasonable chance of identifying areas in the image that will not print the way you want it to.

If you are using a calibrated and profiled screen that is set at an appropriate brightness level (usually less than 100 candela per square meter) and working in a reasonably dimly lit work area (lighting levels at less than 70 lux), the commercial printer should be putting out an image that is quite close to what you see on your screen. If the screen is set to bright, the printer might be decreasing the brightness of your image before printing and that could introduce the posterization. Another possibility is that the posterization comes from how the printer rendering intent is handling out of gamut colours, but if the issue is in the subtle shades, this in likely not the issue.

Just as a final aside, I generally use raw data in the images I print and work in the ProPhoto RGB colour space using 16-bit data (pretty well mandatory for a wide-gamut colour space like ProPhoto). I soft proof using the appropriate printer / paper profile and tweak my print image against an on-screen non-soft-proofed image reference. I generally print on my own photo inkjet printer that uses a 9-cartridge ink set, sending a 16-bit image to the printer. I know other printers that use AdobeRGB as their output profile and some convert to 8-bit. When printing in colour, I have Photoshop manage the colour and when I print in B&W I let the printer driver manage.

[TonyW]

Thanks for all the replies.

Manfred, I should explain that I shoot in raw and use 16 bit processing in Photoshop with ProPhoto RGB. I also have my monitor calibrated although I must confess that the last difficult image I had printed was just after I had upgraded the operating system (on the iMac) and it had upset the calibration without my realising it. It was B&W.

I don't have a photo printer so that I can't print directly from Photoshop myself. As far as I know so far, the lab only accepts jpeg files, either Adobe RGB or sRGB. I will ask them about alternatives such as TIFF or PSD. I have been using their standard lustre paper but again I will try alternatives for other reasons as well. I think the texture of the prints could be improved generally.

Dan, I do see the problem in the files I send, not just the prints.

The question really is whether printing from Photoshop preserves the 16 bit bit depth and whether the printer can make proper use of it.

[Manfred M]

Manfred, I should explain that I shoot in raw and use 16 bit processing in Photoshop with ProPhoto RGB. I also have my monitor calibrated although I must confess that the last difficult image I had printed was just after I had upgraded the operating system (on the iMac) and it had upset the calibration without my realising it. It was B&W.

As the print was a B&W there should be no impact from the profile. If the OS update reset the brightness and contrast settings to the factory defaults, that could have caused some issues.

I don't have a photo printer so that I can't print directly from Photoshop myself. As far as I know so far, the lab only accepts jpeg files, either Adobe RGB or sRGB. I will ask them about alternatives such as TIFF or PSD. I have been using their standard lustre paper but again I will try alternatives for other reasons as well. I think the texture of the prints could be improved generally.

Again, the important part is to ask the commercial printer for their ICC profiles. One thing that I do in deciding on the paper I use is to see what it looks like in soft proofing. Paper choice is about more than just texture and surface finish, it is also about the colour look you are going for. If I can't get the look I want, I will try a different paper.

As a general rule, glossier papers (including luster) are easier to work with than matte papers. Papers than contain an OBE (Optical Brightening Agent) are easier to work with than one without. The trick is determining whether the paper does or does not. Some manufacturers make this easier to figure out than others.

Dan, I do see the problem in the files I send, not just the prints.

In that case, you should not be surprised that this is showing up in the prints. I wonder about your workflow as I have not seen any issues like posterization when I print from the ProPhoto RGB colour space.

The question really is whether printing from Photoshop preserves the 16 bit bit depth and whether the printer can make proper use of it.

I can certainly tell you that I have sent both 8-bit and 16-bit images to the printer. What I don't know is how the printer driver handles them internally. I have not done any extensive testing, but I don't see any differences when I look at an "identical" image that I printed in both 8-bit and 16-bit. The only caveat I'll add is that I did both in the AdobeRGB colour space, rather than in ProPhoto.