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vagn_ebbekier

25 Messages

 • 

620 Points

Mon, Nov 26, 2018 1:12 PM

Photoshop/Lightroom: Are Resolution outdated?

Are resolution outdated? Dpi or Ppi or pixel numbers.

25 years ago we had a screen resolution of 25 Ppi and Apple printers in 640 Dpi.

Today we have screens/tablets/phones of more than 300 Ppi and the best printers use 4800 Dpi or more.

 

Dpi (Dotper Inch)

Historically I think that ”resolution” came from the graphic industry who was the first customers in digital imaging. Also bringing too many saying Dpi, when it correctly is Ppi.

Even Dpi is completely outside the Adobe workflow, since Dpi means ”Dots” (Spots of Paint) per Inch.

This ”painting” process works only in laser-, plotter- and ink-jet printers.

The printer dedicaded software translate the digital picture to the Dpi needed.

The offset and gravure printing process use Lines per Inch. With the ”Dot” size depinding on the physical quality of the paper quality. Translating the Pixels from the digital image demands 1,5-2 Pixels per printing dot. The lines are builded on a separate printing software totally outside Adobe.

So the use of Dpi should today completely be avoided in digital imaging, since this is the mother of confusion. 

Not any single program, or working together in the Adobe Creative Suite needs Dpi.

So get Dpi totally out of the Adobe world!

 

Ppi (Pixelper Inch)

Has been the standard for ”resolution” in the Adobe CC package.

A new blank A-4 Page in Photoshop or best quality In-Design are 3508 x 2480 Pixels in 300 Ppi.

If you, in Image Size change witouth resamling, the pixel dimensions are the same in 72 og 1600 Ppi.

But what is ”resolution” and resolution for what?

To what purpose today do we need the resolution since the ”real” picture/document quality is the pixelsize of the original digital picture t.ex. 8256 x 5504 pixels for the Nikon D850.

All picture quality refer herefrom to the 8256 x 5504 pixels whatever the resolution. 

If you crop it for web to ex. 680x450 Px the picture on the page are exacly the same in 300Ppi as in 72 Ppi.

Export/Save the same RAW picture in 2, 72 and 300 Ppi and in Lightroom and Photoshop the all have the sam file size andwill bee shown exactly the same way in 1:1/100% or 3:1. Even dragging the 72 PPi pict. to the 300 Dpi page in Photoshop.

Exporting to a webpage or PowerPoint do not any more ned to be changed to 72 Ppi (96 on Win). 

The pixel dimension/number of pixels  XxY are in fact the the real quality, not the resolution, and the are in fact no Ppi resolution in the imported picture.

 Are the resolution just a service function we do not need any more?

When exporting to an ink-jet printer you get  the same quality of print of sam size if your picture are in 2, 72 Ppi or i 300 Ppi if it has to be printed in the same paper size size. It is the pixels numbers XxY that counts.

 

Here in Scandinavia the demands for delivery for digital til the printhouses and professional Press Photographers printing A-4/Letter. 

Before it was ”Deliver you photo as Tiff, jpg Max. 25 Mb, RGB, 300 PPi” 

Today it is ” 3500 Pixels on longest side. Jpg best quality” (No resolution named)



What if Adobe completely removed the PPI box?

In Lightroom and Photoshop nothing will happen, and it will be more easy to understand the digital imaging quality and working process. Actions in Photoshop could easily be changed to refer to pixel numbers.

In InDesign, working for both print and screen, it will be a better platform to get a perfect quality for best purposes. But demands a exellent logic explanation, since users are the most conservative ones.

The number of pixels XxY, bit dept and dynamic range in the digital documents are for me the only item in todays Adobe workflow.

 

That said. I ́m educating 400+ in digital imaging in many different types of jobs, and the explanation of picture size and ”resolution” are the most confusing to understand. (Colour managment in CC are more easy to teach) – so my resolution to bring the ”resolution” to the scaffold makes me sleep better and gives more logic.

Vagn-Ebbe Kier/kierphoto.com

 

 

Question

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Updated 

2 years ago

18

5

Responses

olivier_van_bellinghen

7 Messages

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170 Points

2 years ago

Great post ! Working in the graphic industry for 25 years+, I can say that "resolution" is only revelant when it comes to printing the image on real life support (paper, packaging; plastic...) I'm confronted on a daily basis with people outside the graphic community (marketing, sales people...) who have the utmost difficulties to understand the resolution/image size topic, but color management remains an even more alien topic to them :-)

0

0

walter_gronli

14 Messages

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332 Points

2 years ago

The Resolution is a valuable tool. The Image size dialoge helps you understand the printable size of an image. i.e. I get a file that is 72 ppi measuring 712x497 mm - by changing the ppi to 300 I can see that the maximum image size in print is 256x 178 mm. When you change the ppi there is initially no apparent change, but when you place the image in - let us say InDesign - 100% image size will give you 256x 178 mm. You can of course use the unchanged 72 ppi image - but will have to check actual ppi in the links-panel. Being able to place (one-click) the image and see what printing size it has, greatly helps determine lay-out possibilities.

3

vagn_ebbekier

25 Messages

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620 Points

Even working in mm you don't need Ppi. You just change size respectively from the pixelbased items and pictures. (In fact I think that's how InDesign/Photoshop works)
The Crop Tool in Photoshop, PhotoshopRaw and Lightroom Classic and CC are Ratioworking independent og and Ppi and you can write mm in the boxes but it is Ratio tha counts from the original picture quality.

Like

2 years ago

0

walter_gronli

14 Messages

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332 Points

The point is not that I use mm - the point is to be able to see the largest possible print size with a good quality. I do not understand what it has to do with cropping the actual image (changing the pixels) in Photoshop?

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2 years ago

0

vagn_ebbekier

25 Messages

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620 Points

If you wish to change resolution in a 72 Ppi  712 x 497 Px image in Photoshop go to Image - Image size and uncheck "Resample".
Then you get a 300 Ppi with the same pixel dimension 712 x 497.
And the picture is exactly the same, and this can be done a hundred times back and forth without any quality loss. 

Cropping in PS are not "changing the pixels" if first Box are "Ratio" you only erase unwanted pixels/area and keep your resolution.(But not the number of Pixels)
You can fill the boxes in top of the Crop Tool up to your demand: Changing the pixels or not changing the pixels and also work in Centimeter.

"Resample" Change the pixels and PS has to "guess" missing pixels witch gives loss of quality.

Like

2 years ago

0

andrew_rodney

1.9K Messages

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22.8K Points

2 years ago

Resolution can be dots or pixels. 
http://www.digitaldog.net/files/Resolution.pdf
Photoshop and other Adobe app's provide a means to print and printers produce dots so DPI in that context is fair game. 
PPI tells us about the pixels that make up our images and are also fair game. 
All one needs to do (ideally) is simply use DPI when dots are a factor and PPI when pixels are a factor or not use I for inch if you're using another metric of measurement (Pixels per color management). 

Author “Color Management for Photographers"

2

vagn_ebbekier

25 Messages

 • 

620 Points

Yes Andrew. You and I have known this for years. But even today 75% of layOuters or graphic designers calls you back if you send a 4000 Pix picture in 72 Ppi saying:
"Can you send again it in 300 Dpi" 

Like

2 years ago

earth_oliver

Champion

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1.6K Messages

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28.5K Points

Ugh. That's the absolute worst and happens way more often than it should. Even better when they judge hi-res based on the filesize... JPG = low res, TIF = high res.

Like

2 years ago

0

john_nielsen_6237965

31 Messages

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722 Points

2 years ago

One place that it's still important is when type size is specified in Points.  But those are really outdated, too. In fact, just thinking about this, I went into Units and Rulers, and changed it to pixels, since that's how I always work, anyway.

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0

JohnMacLeanPhoto

155 Messages

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2.5K Points

2 years ago

"When exporting to an ink-jet printer you get  the same quality of print of sam size if your picture are in 2, 72 Ppi or i 300 Ppi if it has to be printed in the same paper size size."

Are you sure about that?




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walter_gronli

14 Messages

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332 Points

Yes it is the actual number of pixels that count. 

Like

2 years ago

0

andrew_rodney

1.9K Messages

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22.8K Points

Indeed, resolution is just a 'tag' to allow us to do the math to decide what 'size' some output could be. 
We are referring to what is a resolution tag and it's rather meaningless. It could be 72PPI or 180PPI but it doesn't have an inherent meaning, only what you could produce with the number of pixels you have at your disposal. Work with pixels! For example, let us say you have 1000x1000 pixels to keep the math simple. And to simplify this further, let's only consider the horizontal axis. If you have 1000 pixels and divide that by 72, that is, you provide 72 pixels per inch, you could end up with 13.8 inches using that division (1000/72=13.8). Let's now say you divide up your 1000 pixels using 180 instead. 1000/180=5.5. In both cases, you had 1000 total pixels. The document itself doesn't have a size, other than what space it takes up on your hard drive. The sizes above are examples of what could be produced if you divided up the total number of pixels you have, with some number of which is just a tag within the document. In Photoshop, if you use the Image Size dialog, turn resample OFF (do not allow it to create more or remove pixels), you can enter any value, 72, 180, 1000 into the resolution field and the resulting size is calculated for you. But you haven’t changed the document or the data at all. You just changed a theoretical 'size' if you output your 1000 pixels using that resolution. So again, it's meaningless until you output the data. At that point, lets say you print the image, you can decide how big you wish it to appear and/or how many pixels you want to devote to the output. You have 1000 pixels and someone tells you that you must use 300DPI (which isn't true but that's a different story). 1000/300 would produce a 3.3 inch print. You want a bigger print? Lower the DPI (within reason). You set the DPI for output to use 180 of your pixels to produce 180DPI? You get a 5.5 inch print (1000/180=5.5). 
Work with pixels. That's a fixed attribute of the data unless of course you resample that data (add or remove pixels). 

Author “Color Management for Photographers"

Like

2 years ago

0

nayhem

26 Messages

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532 Points

Might be referring to scaling done by the printer driver, after Photoshop has passed it along.

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2 years ago

0

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