240ppi - 402 ppi ?

D

debrito

Suspended / Banned
Messages
1,410
Name
Paul
Edit My Images
Yes
ok
what does this mean
2541 x 2532 @ 240ppi
now was asked by my local phot print shop to change my ppi to 402 ?
i dont kknow what they mean :thinking: can anyone help :shrug:
 
debrito said:
ok
what does this mean
2541 x 2532 @ 240ppi
now was asked by my local phot print shop to change my ppi to 402 ?
i dont kknow what they mean :thinking: can anyone help :shrug:
Click to expand...

thats the resolution of the image, go into image, image size and change the values to what they recommend.
 
For a definition, just for your understanding, ppi is points per inch, also know as dpi, dots per inch. It is what it is.

The usual amount people use is 200-300 for everyday use. I always have my images (automatically) set at 300.

The internet, images are most commonly resized to 72dpi.
 
If you don't change the actual size of your image, changing the resolution will only affect the size of the printed output.

A 2541x2532 @ 402 ppi is exactly the same size as at 240 ppi - i.e. 2541x2532.

For a change of resolution to have any effect on your image, you need to allow it to be resampled when you change the resolution.
 
Adam Rowney said:
For a definition, just for your understanding, ppi is points per inch, also know as dpi, dots per inch. It is what it is.

The usual amount people use is 200-300 for everyday use. I always have my images (automatically) set at 300.

The internet, images are most commonly resized to 72dpi.
Click to expand...

Which does absolutely nothing ;)

The ONLY time ppi comes into play is when getting images printed, it simply 'tells' the printer what size the image should be.

Try this - resize an image to something you can see on screen, do one at 1 ppi and one at 1000 ppi, then look at them, spot the difference? no!
 
I was under the impression that the reason images are usually resized to 72dpi is for uniformality, for applications such as web design. My web design knowledge is very basic though, so I most likely could be wrong.

If I am, why is it often mentioned? I see it and read it a lot on web design forums, magazines etc etc. This message may go past me (I don't go on this forum much these days), so if you respond, could you send to my inbox too, I would be curious to know. Knowledge is power after all :)
 
For info on '72ppi' looky HERE, there are hundreds (thousands?) of similar links to trawl through as well (Not that I believe everything on the internet!)

It seems to be one of those internet myths that just get repeated everywhere :thinking:

For web design or on-screen display (same thing really) it makes no difference at all, just do the 1 or 1000 ppi test and see for yourself.

If you send off to get a print made it is important to use the recommended ppi figure. The usual figure to aim for is 300ppi. This is the normal figure to use for home printing as well to ensure a good quality image, but all the figure is doing is embedding data in the image file for you, so the printer knows how big to print it, it's just simple maths.

I believe Epson inkjet printers will benefit from using 240ppi (??)
 
The ppi or dpi is just a "scale", and defines for a given pixel resolution what the print size will be.

For argument's sake, suppose your image was 2400 x 2400 pixels. At 240ppi, that would give you a print of 10" x 10". Now if you change the ppi to 402, that's nearly twice the density, so if a printer were to print at 402 dpi, your picture would come out around 6" x 6" :)

The logical argument for getting the ppi/dpi in the picture to match that of the printer is to get the best print quality for a given size. If a printer can print only at 240ppi, there's no point suppling a photo at (for simplification) 480ppi because it could only truly print every other pixel/dot of colour. Or it will be an average of the two pixels. If you supply the photo at a lower ppi than 240, then you'll start getting "aliasing" and the print won't be as clear as the printer could produce under optimal dpi/ppi settings :)
 
NinetyEight said:
For info on '72ppi' looky HERE, there are hundreds (thousands?) of similar links to trawl through as well (Not that I believe everything on the internet!)

It seems to be one of those internet myths that just get repeated everywhere
Click to expand...

Ah, been a few years since I've visited Wayne Fulton's site. Back in the previous century I liked it so much I bought the book.

If anybody's interested, the reason why a lot of digital images show the dpi, by default, as 72 is because it's meaningless. The EXIF standard says that this field should contain the value '72' whenever the dpi value is irrelevant.
 
If your working on a website, you would still need to know the website size in inches no? Like my screen is 22 inches across. Or in pixels across of course.

So if everyone is running at 72, then that makes it easier to work things out, no? If someone wanted to work at 1dpi, then the image will have to be hundreds if inches across, meaning people working on the image will have to convert, either in their mind or for real. Is that not the real reason why 72 is often quoted as the size to use. It makes logical sense in my mind.

I understand the logic of changing the dpi will not effect the image if the size of the image is changed, but if everyone worked at a uniformed size, it makes for easier web design.
 
Adam Rowney said:
If your working on a website, you would still need to know the website size in inches no? Like my screen is 22 inches across. Or in pixels across of course.

So if everyone is running at 72, then that makes it easier to work things out, no? If someone wanted to work at 1dpi, then the image will have to be hundreds if inches across, meaning people working on the image will have to convert, either in their mind or for real. Is that not the real reason why 72 is often quoted as the size to use. It makes logical sense in my mind.

I understand the logic of changing the dpi will not effect the image if the size of the image is changed, but if everyone worked at a uniformed size, it makes for easier web design.
Click to expand...

No, when designing a website nobody works in inches. It makes no difference at all what the dpi value is set at when an image is displayed on a web page - all that matters are the pixel dimensions.

Besides, I'd say that almost nobody has a monitor that's 72 dpi. That may have been the case back in the 1980's. My monitor is around 144 dpi.
 
Adam Rowney said:
If your working on a website, you would still need to know the website size in inches no? Like my screen is 22 inches across. Or in pixels across of course.

So if everyone is running at 72, then that makes it easier to work things out, no? If someone wanted to work at 1dpi, then the image will have to be hundreds if inches across, meaning people working on the image will have to convert, either in their mind or for real. Is that not the real reason why 72 is often quoted as the size to use. It makes logical sense in my mind.

I understand the logic of changing the dpi will not effect the image if the size of the image is changed, but if everyone worked at a uniformed size, it makes for easier web design.
Click to expand...

All that matters in website design/on screen is pixels.
 
Ok, thanks for the replies :)
I always try and learn as much as I can on the technical side of imagery,
so appreciate learning something new.
 
ppi is pixels per inch a scanning term and dpi is dots per inch - printing term
 
Geordi69 said:
ppi is pixels per inch a scanning term and dpi is dots per inch - printing term
Click to expand...

But ppi is also a resolution term, used in printing.
So, for example, you can print at 300ppi and at 600dpi.
 
You must log in or register to reply here.
Back
Top