Lightroom exception to the PPI "rule"

[davidedric]

Hi,

This post is prompted by Binnur's recent question about re-sizing. Binnur, if you are reading this it does not change anything in your thread - it's a very specific point. It's something I picked up in Luminous Landscapes

Lightroom has two different ways of producing a jpeg: export, and print to file. Both dialogues have a PPI setting, but they behave differently.

In regular Export, the "Resolution" PPI setting is meaningless, and can be ignored. No idea why it is there.

In "Print to File" it behaves differently. There the "File Resolution" setting does affect the quality of the final image. A low setting produces a lower quality image. I haven't done any playing around, but it's just something to be aware of.

The other thing to note is that "Print to File" actually produces a jpeg reflecting how the image would look on paper. For example, if the same image printed on paper would have had margins, those margins also appear in the jpeg produced by "Print to File".

Dave

[Colin Southern]

Hi,

This post is prompted by Binnur's recent question about re-sizing. Binnur, if you are reading this it does not change anything in your thread - it's a very specific point. It's something I picked up in Luminous Landscapes

Lightroom has two different ways of producing a jpeg: export, and print to file. Both dialogues have a PPI setting, but they behave differently.

In regular Export, the "Resolution" PPI setting is meaningless, and can be ignored. No idea why it is there.

In "Print to File" it behaves differently. There the "File Resolution" setting does affect the quality of the final image. A low setting produces a lower quality image. I haven't done any playing around, but it's just something to be aware of.

The other thing to note is that "Print to File" actually produces a jpeg reflecting how the image would look on paper. For example, if the same image printed on paper would have had margins, those margins also appear in the jpeg produced by "Print to File".

Dave

I imaging that the 2nd option is simply resampling the image to the pixel dimensions (indirectly) asked for - ie if one has specified a size and a resolution then the pixel dimensions will simply be a product of the two.

[davidedric]

Thanks, Colin.

Having posted, I realised someone might be thinking "Why on earth would you want to print to file".

My local camera club has decided that it will display digital images in its annual exhibition using a flat screen tv. They have asked that all images be provided a specific resolution and at the same aspect ratio as the tv, and if the image has a different aspect ratio to include black borders. That's trivial in Photoshop, or Elements, but the only way I could think to do it in Lightroom is to use Print to File, which is when I stumbled across this feature. If anyone knows of a better way of doing what was asked, I would be interested to hear.

FWIW I decided to submit real prints!

Dave

[pthoutex]

Thanks, Colin.

Having posted, I realised someone might be thinking "Why on earth would you want to print to file".

My local camera club has decided that it will display digital images in its annual exhibition using a flat screen tv. They have asked that all images be provided a specific resolution and at the same aspect ratio as the tv, and if the image has a different aspect ratio to include black borders. That's trivial in Photoshop, or Elements, but the only way I could think to do it in Lightroom is to use Print to File, which is when I stumbled across this feature. If anyone knows of a better way of doing what was asked, I would be interested to hear.

FWIW I decided to submit real prints!

Dave

Dave,
For our monthly competition, my camera club also requires all entries to be no more than 1024 pixels wide horizontally and no more than 768 vertically (following PSA rules). It also happens to be the resolution of our digital projector. To follow the rule, this is what I do in Lightroom when exporting my file.
Under 'Image Sizing' section, check the 'Resize to Fit' box. If you choose the 'Width & Height' or 'Dimensions' option, you can specify the sizes, either in pixels, inches or centimeters for the width and height. At the same time, you can also specify the file size in the 'File Settings' section (above the 'Resize to Fit' section)
I don't know if this will help your case, hopefully it will.

Philip