Since Lightroom is so good, what do you use Photoshop for?

Started 7 months ago | Discussions thread
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Re: Since Lightroom is so good, what do you use Photoshop for?
In reply to soloryb, 6 months ago

soloryb wrote:

Mark K W wrote:

soloryb wrote:

Glen Barrington wrote:

soloryb wrote:

Ron AKA wrote:

soloryb wrote:

Robgo2 wrote:

soloryb wrote:

Actually, if you work in layers, never altering the background layer, Photoshop is non-destructive as well. Files are much larger, but that is another issue.

If you flatten the layers before printing you can do some pixel destruction. Wouldn't that result in a reduction in print quality if there were many layers involved?

Firstly, you should always make a duplicate image for printing, leaving the master copy intact. Secondly, I am not aware that flattening the print file causes any degradation of print quality, even though pixels are altered permanently. Finally, are we sure that Lightroom does not create a hidden converted file as part of the printing process? If so, that would involve altering pixels.


I'm fairly certain that any edits that PS does to an image causes some image degradation as it alters the actual pixels. Flattening just consolidates all those edits, which means that the image pixels have been altered and therefore degraded. I've read (and also always followed this practice) that you should flatten all your layers before sending the image to the printer. That means that after editing in PS and then printing, you are working with a slightly degraded image. The greater the number of edits, the more this is true. I really don't know at what point this makes a difference in the final print.

I know that LR printing involves a complex interpolation algorithm, but this is the first time I've heard anybody say that it might alter pixels during this process and then affect the quality of the final output. One of the biggest selling points for LR is that it never alters pixels like PS can. Could you please say where you got this information?

I'm sure Lr is making a temporary print file as I am not aware of any printer accepting a RAW file for printing. I think the point of "non-destructive" editing is being lost in the discussion. The benefit is being able to go backwards to the original file. I don't believe the benefit is better quality when you finally make a print, as you will convert to a JPEG or TIFF to print at the end of the day anyway.

I don't know what LR is doing after you press the print button. There are no indications that such a temporary intermediate tiff or jpeg is being created - just to interface with the printer. You're left with the original RAW at the end. Somehow I doubt that if there is such a phantom file being created, it's a jpeg.

Could anyone who knows what sort of information LR is sending to the printer please climb in here? I've always assumed it was dealing with the print engine directly from the RAW data of the image.


No print utility can access raw data directly, it might be good to remind ourselves how a raw file interacts with the raw developer:

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Thanks for the link to your article, it explains things well. I specifically want to know whether or not LR actually creates an intermediate temporary tiff or jpeg or any other file when you send an image to the printer or any other output. My understanding was that this is not so.

There has to be intermediary files created. The heirarchy of printer interfaces is complex. Printers are connected to systems via drivers and spoolers, and can sit on shared networks and locally on different types of interfaces. That all has to be abstracted from the application. LR - like any application - must interface to the printer via these so that system print queues are handled properly and jobs started and stopped via those print spoolers services and jobs cached properly in your operating system and any errors (like ink-outs and paper-outs) reported back via the OS. At some time therefore there has to be intermediary print-job file(s), and those can only contain non-lossy bitmapped/raster image-data format for the image content, but they will have MIME headers and metadata wrapped around them for printer control (like layout and paper size ans source info, but much more than that), and can also contain font and color-profile and even (postscript) vector information. I do not know all the exact exact formats used on any given machine as it will depend on each precise installation's operating system and version and printer capabilities and interface language known from the driver interface. You can see the jobs - including those from LR - in your OS print-job queue.

If you want to learn more, you are better searching for e.g. "Windows 7 printing API", or "OS X printing API", "CUPS", "RIP Raster Image Processor" or "Windows print spooler", etc.. You can find quite some info on wikipedia and the MS and Apple sites as well as others.

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Thanks Mark,

I realize that the process is complex and may involve some sort of intermediate files. My question was specifically directed at the notion that LR has to create either a jpeg or a tiff before handing off to the printer. I didn't think that was true and your response and Glen's have confirmed that for me.


Sorry to grab you on another one. But what Mark said implies that LR does need to create the intermediate file. Take CUPS for example above, it has various filters that will convert various image formats to a bitmap for printing, but RAW files are not one of those things, so LR actually must hand off some other file between itself and CUPS, it probably exports a bitmap directly but that's just my best guess.  If we were talking about a program with a file that was already in a format that a driver or CUPS filter, etc.. could convert then what Mark said would have supported your thoughts on this.  Then again, the file held in RAM for the editing it probably already a bitmap, but that is approximated for speed during editing, so it likely still needs to generate the file for print.

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