How To Guess The Print Size Of The Image

[Mainecoon364]

I want to know the size of the image I downloaded from internet in centimeters.

 

So I can guess the exact size of the printed image on T-Shirts.

 

On Affinity Photo I can see the centimeter equivalent of the image.

 

An Image I downloaded is 2314 x 1315 pixel

 

And the centimeter equivalent of it is 21159216.1 x 120243.6 centimeters

 

Centmeter value looks immense.

 

So what’s going on?

[walt.farrell]

33 minutes ago, Mainecoon364 said:

An Image I downloaded is 2314 x 1315 pixel

 

And the centimeter equivalent of it is 21159216.1 x 120243.6 centimeters

Those cm values do not make sense. Are you sure you copied them correctly when you posted here?

[Mainecoon364]

You can check them out.

 

???

[walt.farrell]

Can you share the .afphoto document, too?

[Mainecoon364]

Here is the file in .afphoto format.

 

 

???

Affinity Image Size Cm.afphoto

[Alfred]

26 minutes ago, NotMyFault said:

the cm size only depends on chosen DPI and pixel count. So you can set it as you like it

A cm size of 61.22 × 34.79 for an image whose pixel dimensions are 2314 × 1315 implies a DPI value of 96, which is rather low for printing.

[Alfred]

On 6/8/2023 at 6:37 AM, Mainecoon364 said:

You can check them out.

When I looked for that photo (Metallica frontman James Hetfield on stage in 2022) online just now, I found it labelled as “© Getty”. Knowing how fiercely Getty protects their copyright, you would be well advised to avoid commercial use of the image without permission.

[iconoclast]

Just for the case that is not clear to you: There are two important values for printing: the resolution/size of the image in pixels and the relative resolution in Pixels per Inch (PPI or DPI). The relative resolution for print should usually be  ppi/dpi. You can change the relative resolution by resizing the document without Resampling. In that case, the amount of pixels of the image will not change. But if the image has not enough pixels, you will possibly not get the image size in centimeters you want or need for printing. For this you would need to resize the image with activated Resampling. But in that case the amount of pixels will change and that will affect the quality of the image. That's simply physics. Think of that pixels are only tiny squares that contain only one colour per pixel. So a pixel image is in fact a kind of mosaic.

The most images you can download from the internet are too small for printing, and it is not recommendable to increase them to a print size, because they will get a bad quality this way in the most cases. Also think of that printing is expensive and irreversible. So if you want to print something, take care that it has a good enough quality and a size that is big enough, right from the start.

I'm not sure if this helps for this certain case. But, by the way, if it is a Getty Image, you should remove the file from this forum, to prevent legal trouble.

[Mainecoon364]

Note! : I will delete the image here after as soon as I get the answers. Absolutely I won’t print that image. I’m just trying to learn the subject. (I use the image here for only EDUCATIONAL PURPOSE)

 

Question 1) When I set “Documents - Resize - At the bottom menu - Units - Centimeters”

It shows

231.40

131.50

(Although Pixel Dimensions are same with yours!!)

Why? Can you try?

 

Question 2)  Can you tell me what should be 

 

A) Resolution

B) DPI 

 

values should be for 

 

A) 30 x 30 cm size print

B) 40 x 40 cm size print 

C) 30 x 40 cm size print

 

and explain me how do you calculate those?

 

Question 3) As far as I understand 

 

A) I can change DPI as much as I want without losing quality. (Decreasing and Increasing) (You can change the relative resolution by resizing the document without Resampling.)

 

B) I can decrease the size of the image without losing quality.

 

C) I can NOT increase the size of th eimage without losing quality.

It requires upscaling and It can be done on Dall-E 2 as far as I know.

 

Am I right?

 

[NotMyFault]

Q1: 
When the resize UI is open, click on the small white arrow to the right to see the 2nd page. There you can inspect and adjust the dpi setting. Use some reasonable value like 72, 96, 150 etc.

it showed 96 dpi on my iPad, you probably have a much smaller value.

[Mainecoon364]

I have 96 dpi as well. 

 

Can somebody answer my questions please?

[Alfred]

5 hours ago, Mainecoon364 said:

“Documents - Resize - At the bottom menu - Units - Centimeters”

The “bottom menu”? In APh on iPad??
Edit: I overlooked the fact that we’re discussing version 1 of APh, not version 2.

5 hours ago, Mainecoon364 said:

It shows

231.40

131.50

That corresponds to only 10 px/cm, which is an extremely low print resolution for anything less than billboard size.

4 hours ago, Mainecoon364 said:

I have 96 dpi as well. 

 

Can somebody answer my questions please?

I think we have some missing and/or conflicting information which is getting in the way of providing helpful answers.

Edited June 9, 2023 by Alfred

[walt.farrell]

There is something odd going on in Photo 1.10.7 on iPad, with the Document Resize process.

Sample file, and video below.  In the video, I start with the file already open, but have done nothing beyond Open. I then initiate a Resize, and switch from Pixels to Centimeters and get a ridiculous value. I then tap Reset, and have the wrong Pixel value, too.

 

[NotMyFault]

Yeah, when using resize document, deactivate resample, conversion from cm to px gets totally wrong.

[walt.farrell]

11 minutes ago, NotMyFault said:

Yeah, when using resize document, deactivate resample, conversion from cm to px gets totally wrong.

Thanks, but it doesn't seem to matter whether Resample is active or not. Converting from px to cm and back, possibly a couple of times, and the sizes get very strange.

[NotMyFault]

Good analyses so far. As far as I understand the messages from Affinity, V1 won’t get any functional bug fixes except the App becomes completely unusable caused by newer OS releases (e.g. impossible to install, start, save files etc). So users have to accept this bug and try to use workarounds.

Possible workarounds:

• try resize at export instead resize document
•  

[Mainecoon364]

Question 1) Did you try resizing at export? Did that work?

 

Question 2) Does Affinity Photo V2 have the same problem???