Bridge 8.X update defaults to 72dpi

[juddd29301065]

Since updating to the latest version of Bridge I notice that any .png or .jpg I Save As in PS will display in Bridge as 72dpi. Previous versions always displayed in 300dpi or whatever resolution I saved as. When I open these files in PS the image size is correct at 300dpi, but Bridge still says the resolution is 72dpi. This is very annoying as I don't know what resolution my files actually are now. Help!

[Stephen_A_Marsh · Accepted solution]

Quick Answer:

There is of course interplay between the program saving the PNG file and the program viewing the PNG file. Then one must take into account the PNG specification and whether a program is adhering to the spec. PNG files are intended for monitor use, so resolution metadata may be considered irrelevant by various software or users.

Photoshop Save As will retain resolution metadata, however depending on the version of Photoshop this may or may not be what you think it is.

Photoshop Export/Quick Export strips the resolution metadata, as does Export/Save for Web (Legacy).

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Longer Answer:

The PNG specification does support resolution metadata (PNG-pHYs PixelsPerUnitX & PNG-pHYs PixelsPerUnitY) – however the official specification for the resolution unit is in metres (not inches or centimetres)!

So a PNG that is 2880x1800px and setup in Photoshop as being 288ppi:

[PNG]       ImageWidth:      2880

[PNG]       ImageHeight:     1800

[PNG-pHYs]  PixelsPerUnitX:  11339

[PNG-pHYs]  PixelsPerUnitY:  11339

[PNG-pHYs]  PixelUnits:      meters

113.39cm x 2.54cm = 288.0106 ppi (rounded to 288 ppi). This is what Photoshop is doing when it opens a PNG image that contains resolution metadata. Otherwise the displayed resolution is set as 72 ppi as a default if there is no resolution metadata in the file.

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Bridge CC2018 may indicate that a PNG file has a 72 ppi resolution, however this is just a “helpful” arbitrary default resolution value rather than showing as blank. I personally would find it more helpful to simply show this value as blank or not show the data at all as was the case in CS6.

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At one point in time, at least for CC2015, Photoshop was adding in extra metadata that was not to the PNG specification. The extended metadata was:

[XMP-tiff] XResolution: 288

[XMP-tiff] YResolution: 288

[XMP-tiff] ResolutionUnit: inches

And this metadata addition did allow Adobe Bridge to display a resolution entry… However Adobe stopped doing this and now things are back to “normal”.

So if one wishes to add this data back in (which is not to specification and may or may not cause problems in various software) so that Adobe Bridge can show a PPI value, the ExifTool command would be:

exiftool -XMP-tiff:XResolution=288 -XMP-tiff:YResolution=288 -XMP-tiff:ResolutionUnit=inches -r -ext png 'path to top level folder or file'

EDIT: There may be a Bridge script option available, however I could not get it to work:

Re: change resolution

[forebrain]

I just discovered today that Bridge displays my PS files (saved in 300 dpi) as 72 dpi. I was a little perplexed and decided to google for solutions. I'm glad I found your answer here and decided to ignore this issue. Thanks for sharing.

[JJMack]

How do you save the files in Photoshop? Save as,  Save for Web or  Export.  Save for Web and Export may save no DPI print resolution setting in the image files for thy are intended for the Web. Where all the matters are the pixels you save for web devices do not use any DPI setting they use the own resolution the only resolution they can.

If you open a image file in Photoshop that has no DPI print resolution setting Photoshop will default the resolution to 72DPI.  You can change a Document resolution to any value you want using Image size uncheck Resample and set the Resolution that you want the image to have. Not a single pixel will be changed only the Print DPI resolution setting will be changed.

What matters are the number of Pixels you have and their quality. 

[Curioso]

I'm like you.

Although the .png format is for viewing on the screen, there are situations in which you need an image with transparency, resolution suitable for printing and isn't possible to use .psd files.

PNG is the solution and if  don't show the resolution it has even if it doesn't meet a standard, it's annoying

[JJMack]

Are you using  Save As, Export or Saved for Web.   If you want the print DPI resolution set use "Save As" . Do not use save for web or any other export options perhaps also not Adobe Generator Plug-in.    Use Photoshop "Save As" Or "Save" If it is a single layer and the image window or tab shows DocName.png

[Curioso]

I always use the commended save as and it does not work. It only indicates 72ppp. Knowing that it is a Bridge issue and that it does not seem that we do anything wrong at the time of saving, I will not give much more importance.

The same in the future they solve it.

[Stephen_A_Marsh]

That is correct, Bridge CC2018 will ignore the resolution metadata in save as PNG, however Photoshop will “translate” the same resolution metadata. So there will be a discrepancy between the two. I preferred the behaviour in Bridge CS6, however it could be argued that Bridge should also perform the same “translation” as Photoshop. Another view could be that Bridge should show the resolution value from a Save As PNG using pixels per metre as per the PNG specification.

So there we have it, four possible representations of the same file that could be considered as “best”, depending on your viewpoint. What a mess.

[JJMack]

I would vote for it there is a settng stored in the file use and display that setting.

[Stephen_A_Marsh]

I would vote for it there is a settng stored in the file use and display that setting.

That would be the logical thing to do JJMack, so a save as from Photoshop would result in:

Photoshop reported resolution of 72 ppi = Bridge reported resolution of 2835 ppm (pixels per metre)

Photoshop reported resolution of 300 ppi = Bridge reported resolution of 11811 ppm (pixels per metre)

Which arguably would lead to just as much confusion as a 300 ppi Photoshop image being displayed as 72 ppi in Bridge. So logical is not always the best when we take end user expectations into account, as the majority of users are blissfully unaware of these issues.

So for what it is worth I personally would vote for one of two alternatives. I am now leaning toward the second alternative for consistency:

1) A return to CS6 behaviour, where no PPI value was indicated for a PNG, whether it was from a save as (resolution metadata included) or an export/save for web (resolution metadata excluded).

or

2) The same “translation” as performed by Photoshop, where resolution metadata is in the file – then conversion to ppi or defaulting to 72 ppi for images without resolution metadata. At least both Photoshop and Bridge would agree on the resolution value, even if this was all fiction!

[Lumigraphics]

If you Save for Web, check your metadata settings. If the TIFF namespace is removed, ppi information won't be retained.