Saving a Tiff file to scale

[GLW]

Hi,

I have a file I've made on Affinity Designer to be sent to a print manufacturer. They want a 300dpi Tiff file to scale, but every time we convert it the size changes?

Any help would be greatly appreciated.

Thanks.

[Pšenda]

Menu File, Document Setup, Objects will: Rescale?

[GLW]

It seems to save the same.

The file says dimensions are 7678 x7678, and the dimensions we need are 650mm x 650mm

A converter tells me this is the same thing but the printer says it is only 4cm x 4cm.

Does this make sense?

[Pšenda]

2 minutes ago, GLW said:

The file says dimensions are 7678 x7678

Units?
"The file says" - you mean document? Document Setup screenshot - before and after DPI changing?
"A converter tells me" ???

[GLW]

Here are the dimensions of the file: 

And here is a converter I used to calculate what px dimensions 650mm would be equal to:

[GarryP]

You are converting between millimetres and pixels per inch (PPI).

Since millimetres and inches don’t don’t normally divide into each other very nicely you will normally get something after the decimal point.

How the software works with those decimal places depends on which software and what you’re doing with it.

This is to be expected.

[GLW]

Hi Gary,

I understand this, I would be happy with it being 7678 or 7677 px, but the issue is that this is coming up as 4cm^2 for our printer, not 65cm^2, as it should, not the decimal place.

[David in Яuislip]

mm                        in                 dpi                   px
650    25.4    25.59055118    300        7677.165354330710

 

I reckon the printer is wrong

[Old Bruce]

1 hour ago, GLW said:

I have a file I've made on Affinity Designer to be sent to a print manufacturer. They want a 300dpi Tiff file to scale, but every time we convert it the size changes?

Are you resampling when you convert? What is the DPI/PPI of the original? What is the size in mm of the original?

[GLW]

 

3 minutes ago, Old Bruce said:

Are you resampling when you convert? What is the DPI/PPI of the original? What is the size in mm of the original?

Here is the document set up:

And here is the Export panel:

Does this make sense?

 

[Old Bruce]

That should work. I am going to go along with @David in Яuislip. The printer has perhaps given you a too low PPI/DPI setting.

[Pšenda]

1 hour ago, Old Bruce said:

too low PPI/DPI setting

Too high (4cm = 1.575 inch, 7678 px / 1.575 = 4875 DPI - really weird value).