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heskphotography

EXIF file loss and DPI not holding after changing

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One of the site I post photos to, require 300DPI and the EXIF file as proof of ownership. My raw files are always 72DPI in Affinity. When I create a new blank photo document its at 300DPI.

I paste the photograph onto it and the photo DPI changes to 300DPI. However, the EXIF file is lost. If I don't past to a blank document, but change the DPI from 72 to 300 on the original developed photo and export it to Tiff, the DPI reverts back to 72 in my tiff files. The photo on the Affinity interface is still 300 DPI. The same thing happens if I export to Jpeg. 72 DPI is no good for prints. It needs to export at 300 and still retain the EXIF file.

Thanks 

heskphotography.

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My raw files (Nikon D5100) come into Affinity Photo as 300dpi, and when exported as TIFF are still 300dpi, so I'm not sure why yours are coming in at 72dpi.
My exported TIFF file also retained the EXIF data.

What kind of camera are you using? Can you attach a sample raw file here for us to look at?

What version of Affinity Photo do you use, and on what OS?
 

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Hi Walt. Thanks for your reply. I use a Canon 80D. When I used Photoshop, my raw files were at 300 DPI and stayed that way unless I changed them.

My Affinity Photo is 1.6.4.104 and there is a raw file attached. If I leave it at 72 the EXIF data is retained. If however, I create a blank document for photo which automatically is 300 DPI and paste onto it. The EXIF file is lost because the blank document doesn't have an EXIF file. Op system is Win 10.

IMG_5702.CR2

Edited by heskphotography
missed off answer to question. i. e. Win 10.

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You can change it to 300dpi and preserve that setting by using the More button during export, and unchecking the metadata box.

However, that will lose your EXIF data.

Sorry, I don't have a solution for you; perhaps someone else will have an idea. I can say, though, that I understand why your images come into Affinity Photo at 72dpi: that's what your camera recorded in the EXIF data it provided with the file.

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Hi there, just tested this... this is the fix ...

Where you're going wrong is placing the raw file into a new document.. and that would eliminate the EXIF..

What you NEED to do.. is open the raw file directly in Photo... it will open directly in the Develop module, make any raw edits if needed and hit the develop button.. if you check the image specs through the Document menu (resize document) you will note that the image SHOULD be @ 300dpi and if you invoke the EXIF studio you will still find the exif info still present, then if you export that file to jpeg, it will export to a 300dpi jpeg with the exif in tact.. I assume that's what you're after! I hope that helps!

Cheers!

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Hi heskphotography,

Unfortunately there is a known issue where the DPI is not being retained when exporting  As Walt has said above, the only way to get around this is to untick 'Embed Metadata' which is not ideal for your situation either.

I'll get it bumped with development.

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No no no I found it!! I found out what you need to do...

Step 1. Open the RAW file to the develop module (it will do that automatically)

Step 2. Edit the RAW file or just click on develop to Photo..

Step 3. Resize Document: Uncheck resample and select 72dpi and hit Okay..

Step 4. this is where the magic happens go to the layers palette and right click on the image and click on RASTERIZE..

Step 5. Export to Jpeg at current dimension or new dimension and save..

You should now have a 72dpi jpeg WITH EXIF... can you try that please??

Cheers!

 

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Oh.. .sorry my bad.. I'm having a game going the other way! my NEF file comes in at 300dpi and I'm trying to export to 72dpi I think I've opened myself a can of worms here!! LOL!

 

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Sorry Walt but you've got it wrong. My camera produces 300DPI as a raw file. If it didn't the raw EXIF metadata would not show a file size of 6000 x 4000 at 35.5MB, it would be considerably less. It is AFFINITY that is converting it for some reason. I can retain it at 300 DPI by converting it from 72 (caused by AFFINITY) back to 300, by pasting it to a new transparent Doc, but the EXIF metadata is stripped out. 72 DPI has a file size of 1.15MB. A raw file of 72DPI would have holes everywhere. However, it is not possible to set my camera to take 72 DPI raw in either my 50D or my 80D. However, I may have thought of a work around myself that will suite my purpose. I'll let you know if it works.

DegasBrush. I want to retain 300DPI AND the EXIF file.

PS Photoshop never converted any of my files to 72 DPI unless I specifically instructed it to do so. The fault lies within AFFINITY.

Cheers.

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10 minutes ago, heskphotography said:

Sorry Walt but you've got it wrong. My camera produces 300DPI as a raw file. If it didn't the raw EXIF metadata would not show a file size of 6000 x 4000 at 35.5MB, it would be considerably less. It is AFFINITY that is converting it for some reason.

The EXIF data as displayed in the Develop Persona for your photo shows a TIFF x-resolution tag of 72, if I remember correctly (I'm away from my computer right now). 

I suppose it's possible that Affinity Photo had already adjusted the original value recorded by your camera, but it doesn't do that with my camera.

If you have some other tool that can display the EXIF data that's in your file you should be able to tell. I'm not sure I have one.

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Hi Walt. I can see where you are coming from now. The raw file is converted to 72 on entering Affinity in the Developing Persona. So that must be where the fault is.

The only other tool that will show that, is Photoshop which I no longer have. Unless GIMP shows it. I'll have to download it and check it out. Get back to you on that.

Thanks Walt.

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Affinity Photo includes a copy of "exiftool.exe" which I ran manually against your IMG_5702.CR2 file. I've attached its report, which agrees with what Affinity Photo displayed in the EXIF panel of the Develop Persona. Apparently your camera is saying it's a 72dpi file.  IrfanView also agrees that the camera's EXIF data says it's a 72dpi image.

Relevant excerpt from exiftool:

Quote

X Resolution                    : 72
Y Resolution                    : 72

I've found at least one site that claims that some digital cameras just put 72 in there because it's a traditional dpi for computer screens.

img_5702.cr2.exif.txt

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23 minutes ago, walt.farrell said:

I've found at least one site that claims that some digital cameras just put 72 in there because it's a traditional dpi for computer screens.

The value 72 is traditional for the DPI on Mac screens, but on Windows the traditional value is 96. In both cases the inches are only ‘logical’ inches, so the value is of little use beyond setting up the computer’s display parameters.

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[First part of this post was made at the moment of the update]

I'm not sure about the "SHOULD" be at 300dpi…

The developpment of different RAW files is at different dpi, as @walt.farrell said :

  • CR2 => 72dpi
  • DNG => 96dpi
  • ARW => 350dpi
  • RW2 => 180dpi

But you can modify the value (Ctrl+Alt+I) Document > Resize document (don't check  "resample")

 

[Second part]

I checked with different applications (couldn't find informations about dpi on Darktable):

RAW   |   XN  |  AP   |   RT |  IV   |
======================================
CR2   |   72  |   72  |  300 |    72 |
DNG   |   72  |   96  |  300 |    72 |
NEF   |   72  |  300  |  300 |    72 |
ARW   |   72  |  350  |  300 |    72 |
RW2   |   72  |  180  |  300 |   180 |

AP = Affinity Photo
IV = IrfanView 64
RT = RawTherapee
XN = XNview MP

 

I'm wondering if there's any information about dpi…

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Hi Walt. I put a raw photo into my Canon professional photo processing programme and it was 350 DPI Tiff EXIF. then I put it into AFFINITY photo persona and it stayed at 350 DPI. I then put the same raw photo into the develop persona and it was at 72 DPI. That tells me that the develop persona is causing the problem. Just re checked it and it's still 350DPI. Then I put it into develop persona directly from the photo persona and it stayed at 350. Plus the EXIF file wasn't deleted either So it seems to be when the raw file is presented to the develop persona. Sean seems to be of the opinion that it is a long standing problem that doesn't effect every ones copy of Affinity.

So I've found a work around of sorts. But it's not ideal as I have to use two separate processing programmes. My Canon one for the raw and Affinity to finish it off.

Thanks guys for your efforts.

Roy.

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The only important part is the width and height in pixels.

dpi is only an information about at which "scale" to display your image (print, web…).

For exemple: if I've got a 600×600px image, I know I can print it professionnaly at 2×2 inches, since it needs 300ppi. 

For Internet* display, we usually use 72dpi: 600/72 => at 72dpi, it would be diplay — when setting dpi at 72 — on a surface of 8.3×8.3 inches.

You can process your RAWs files with AP and use a simpler program to modify the dpi information (without resampling the file) later (AP and other apps get the same pixel width and height for the same raw file without error).

 

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2 hours ago, heskphotography said:

I put a raw photo into my Canon professional photo processing programme and it was 350 DPI Tiff EXIF. then I put it into AFFINITY photo persona and it stayed at 350 DPI.

You can't put a raw photo into  the Affinity Photo Photo Persona, as the Photo Persona deals only with already developed photos (e.g., jpg, tiff, image data from the clipboard, etc.).

Your camera is recording incorrect information into the EXIF data, as we can see from exiftool, IrfanView, and other programs. It may well be that some other programs ignore that data, but Affinity Photo does not. When the data is recorded in the file, Affinity Photo uses it.

The fact that Affinity Photo uses it may be a bug, given that many cameras seem to record it incorrectly. Or it may be an opportunity for enhancement. Only the developers would know.

We do know that they agree with the need to enhance (or fix) their EXIF processing when exporting files. When they do that, then it will be feasible for you to fix your camera's incorrect data inside Affinity Photo by resizing the photo and respecifying the DPI. Until then your only choice will be to use a separate EXIF editor, or a different photo editor. You can probably find some free EXIF data editors if you look.

 

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Hi every one.

I've sorted the dpi and ppi definitions. PPI is the number of Pixels Per Inch on a computer screen.

DPI is Dots Per Inch in a print. So Raw in Affinity, in the EXIF file is at 72ppi. That is 72 Pixels Per Inch on the 'X' axis, i.e. left to right for every inch there is 72 Pixels. In the 'Y' axis i.e. up and down. there is 72 Pixel in every inch. So for every square inch of screen there is 5,184 pixels in one square inch. Which is correct for a computer screen.

Similarly, on a print there is 300 Dots Per Inch or DPI for every linier inch of print. Or 90,000 dots of ink per square inch. That would give me a great A3 print. I've even had a great print at A2 with 300 DPI.

I prefer a print of at least A3. Can you imagine what an A3 print would look like at 72 DPI. It would be a mass of holes and the print would be mush. Which is why 72DPI would make an awful print.

That's why it's always wiser to set your DPI to 72 on a Jpeg for the web. Then if anyone tries to print it, it would be rubbish.

This is why Affinity is causing me grief at 72 DPI in a Tiff or Jpeg when changing from the Develop Persona, to the photo Persona. When I set the DPI in Develop to 300, it should still be at 300 DPI when it is opened in the Photo Persona. But it isn't it's changing the DPI back to 72.

I tried it in the Canon Raw developer and it stayed at 300 DPI when put into the Affinity Photo Persona. It works but it's not ideal, because the colour adjustments in Canon Raw Developer. isn't as good as in Affinity Develop. This did not happen in PS, so clearly, there is still some work to do with Affinity.

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16 minutes ago, heskphotography said:

That's why it's always wiser to set your DPI to 72 on a Jpeg for the web. Then if anyone tries to print it, it would be rubbish.

If anyone tried to print it at 72 dpi it would look very poor. At 144 dpi it would look OK from a couple of metres away, but its area would be only a quarter of the size of the 72 dpi version. Regardless of the DPI value stored in the file, the pixel dimensions are what matter for display on a computer screen; a 7 dpi image will look exactly the same on your monitor, but would be huge (and extremely low quality) when printed at native resolution.

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Really, all that ever matters for print is pixel dimensions and their relationship to effective dpi/ppi.

Well, and the quality of image. 

The dpi field in an image is informational only and simply is ignored on the web where the only thing that matters are pixel dimensions. 

Sorry if this all has been covered in this thread...

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1 hour ago, heskphotography said:

When I set the DPI in Develop to 300, it should still be at 300 DPI when it is opened in the Photo Persona. But it isn't it's changing the DPI back to 72.

How are you "setting" the dpi in the Develop Persona?

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I'm not setting DPI in Develop. It comes into Develop at 72 PPI not DPI. When I put it into Photo, that's when I convert it to DPI. Then when I export it and check the Details in Properties, the DPI is back at 72. On exporting to Tiff it changes back to 72.

So I uninstalled AFFINITY and reinstalled it to see if a clean install would cure it, but it hasn't, it's still there.

According to Sean, this is a known issue which only seems to be a few programmes. but he's trying to get it sorted.

So we shall see.

Thanks Walt.

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Using the term "dpi" can be confusing. 

In fact, only your printer (desktop or man) now about its/his dpi.

On your file you only have pixels.

We usually assume that for printing 1 pixel (screen) = 1 dot (printer).

Al that matters is how much pixels you need to print on x*y surface.

And usually, on your deskjet printer you'll fit to page or at x%.

What I means is develop yours pics,  change "dpi/ppi" later with or without AP, but there's no need to see drama where there's none.

 

Edited by Wosven
Edited for typos when typing on my phone :S

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