Resolution & Pixel

[MahaB82A]

Is it possible to have number of same images but different resolution in the same canvas? I tried but it does not work.  Resolution of all images default to resolution of last image. 

[davescm]

Images can have different pixel sizes when contained within smart objects, but will alsways be displayed using the pixel size of the 'master' document.

Resolution, in terms of ppi, is not used on screen - only in printing and an image document can only have one value which determines the physical size when printed.

Dave

[Stephen Marsh]

@MahaB82A – Resolution, as in the metadata entry for PPI or PPCM, is a property of the document, not the layer.

[Nancy OShea]

For consistency,  create a new canvas with your desired dimensions, PPI, color mode and background.

Go to File > New...  See screenshot.

Place or copy and paste images into the newly created canvas.

Adjust layers to suit.

Save file.

Hope that helps.

[barbara_a · Accepted solution]

No, it is not possible. Each individual Photoshop image can have only one resolution.

[MahaB82A]

Thanks for the explanation.

[MahaB82A]

Does it mean size of a image in print out only?

[davescm]

Yes, 

Any physical measurement such as inches or cm is referring to print size, and is a simple calculation of pixels/ppi.

On screen, ppi of the image is irrelevant and the size on screen depends on the pixel density of the monitor on which it is being viewed.

Dave

[MahaB82A]

Pixel is a computer unit, inch is a physical unit. If resolotion say 300 ppi. Have we to assume that there are 300 pixels in one inch length of the image printout? If so, ppi mearly creates a relation between computer unit & physical length. 

Is there any relation between ppi & dpi?   

[davescm · Accepted solution]

You've got it 🙂

ppi (literally pixels per inch) is the unit used in Photoshop, and other imaging software, to convert pixels into a physical size on paper. There is a lesser used but equally valid ppcm (pixels per cm) for those working in metric.

dpi (dots per inch) is often, incorrectly, used interchangeably with ppi. But dpi is a different measure and refers to the dots used by the printer to make up the individual pixels on paper. So, for example, you might see an inkjet printer which lays down 2880 dpi. That does not mean the printer can print 2880 ppi. 

You might also come across lpi (lines per inch) which refers to the screen used in some printing techniques when printing to a physical media.

Dave

[MahaB82A]

Thanks for the explanation.