silly printing question

[Robbo]

Basically, if I send a print off, am I best to resize it to the right size and PPI that I want it printing to, even it if re samples DOWN, or would I still get the same quality print if the image is larger than the print size.

e.g. (figures not correct at all btw just to show what I mean)

Actually picture, 4000x3500px

Print needed, 10"x8"

to print that picture out at that size the PPI would be say 800. so there is technically too much information there that isnt going to get printed. will I get a better result if I re sample the image to the correct size, reducing the px.

e.g.

from 4000x3500px resize to 2000x1500 300PPI to give 10x8

 

[Chappers]

It depends on the printer you are using. Most will happily downsize to the required printing resolution. Others require the image to be resized to a specific dpi. When in doubt speak to the company concerned. They will tell you the best way to send the file for printing

 

[Robbo]

It depends on the printer you are using. Most will happily downsize to the required printing resolution. Others require the image to be resized to a specific dpi. When in doubt speak to the company concerned. They will tell you the best way to send the file for printing

Cheers.

I never had problems before it was just something that popped in my head lol

 

[EOS_JD]

Basically, if I send a print off, am I best to resize it to the right size and PPI that I want it printing to, even it if re samples DOWN, or would I still get the same quality print if the image is larger than the print size.

e.g. (figures not correct at all btw just to show what I mean)

Actually picture, 4000x3500px

Print needed, 10"x8"

to print that picture out at that size the PPI would be say 800. so there is technically too much information there that isnt going to get printed. will I get a better result if I re sample the image to the correct size, reducing the px.

e.g.

from 4000x3500px resize to 2000x1500 300PPI to give 10x8

i would downsize for one simple reason - the file size. it will be faster to download a 3000x2400pixel image

from 4000x3500px resize to 2000x1500 300PPI to give 10x8

Just a point regards the above - I'm not sure you understand the maths behind the pixel data you just provided.

To print a 10x8 at 300ppi you need 3000 x 2400 (multiply 10x300 and 8x300).

A 2000 x 1500 image at 300ppi would give a print size of 6.667" x 5"

Print Size (PS)
Pixels (px)
Resolution (R)

Px = Ps x R
Ps = Px/R
R = Px/Ps

that should help you resize your images correctly - do the calculation twice - once for each axis of your image as noted above

 

[EOS_JD]

It depends on the printer you are using. Most will happily downsize to the required printing resolution. Others require the image to be resized to a specific dpi. When in doubt speak to the company concerned. They will tell you the best way to send the file for printing

You resize to a specific PPI (should not be DPI although I appreciate people use the term dpi to mean ppi). oth are different.

One is an image resolution - ppi
The other is a printer resolution (dpi)

 

[Robbo]

i would downsize for one simple reason - the file size. it will be faster to download a 3000x2400pixel image

Just a point regards the above - I'm not sure you understand the maths behind the pixel data you just provided.

To print a 10x8 at 300ppi you need 3000 x 2400 (multiply 10x300 and 8x300).

A 2000 x 1500 image at 300ppi would give a print size of 6.667" x 5"

Print Size (PS)
Pixels (px)
Resolution (R)

Px = Ps x R
Ps = Px/R
R = Px/Ps

that should help you resize your images correctly - do the calculation twice - once for each axis of your image as noted above

Thanks for the info but I do understand about the terms etc, I did say at the beginning....

'Robbo - e.g. (figures not correct at all btw just to show what I mean)'

The file size doesn't matter as it's being put on a cd. So download time doesn't come in to it.

I done 5 test prints all set to 8x6, 300ppi, 240ppi, 180ppi, 120ppi and 90 ppi....... All printed at 300DPI

From 180 to 300 pretty much no different that i could see. At 120 could see some slight softening in areas, and 90 looked very soft.

 

[EOS_JD]

Now I see what you mean

Yes I print down to about 150ppi for very large images. For smaller I generally keep to 240ppi minimum but have printed crops at 200ppi and like you say hardly any difference - if at all!

 

[Robbo]

Now I see what you mean

Yes I print down to about 150ppi for very large images. For smaller I generally keep to 240ppi minimum but have printed crops at 200ppi and like you say hardly any difference - if at all!

I'm not the best at explaining things lol

I was quite surprised at the test, I was looking really close too, so from 'normal' viewing it would be impossible to tell

 

[snappingsam]

Sending a file to print with more than 300ppi (or 360 if you use some inkjet printers) will just slow down the printing - and if you are sending to an online printer, the time taken to upload. Also be aware that some online labs resample your file to reduce the size in the background.

As Robbo states - its hard to tell the results from normal viewing distances with undersampled files - my lab regulary prints for one photographer in particular who sends in everything sized as 5"x7" @ 300ppi - and the 12x15's look really quite good!

 

[AndySP]

If you're sending on a CD, send the highest res version you have. Many commercial printers will print at about 1200 dpi, so the more info you can give them...

As for printing at home, I keep all my images at 300 ppi tiff files unless I need them at A3+ and then drop to 240ppi. For canvas, I use an external printer and resize to their requirements to allow for wrapping around the frame etc (you can go quite low on canvas with no obvious loss of quality).

As others have mentioned though, don't get ppi and dpi confused - as I say, my images are stored as 300 PPI files but the lowest res my HP A3+ will do is 600DPI (with options to go 1200 DPI). PPI & DPI often get confused... My A3+ prints are 240PPI printed at 1200DPI for maximum quality.

 

[Robbo]

If you're sending on a CD, send the highest res version you have. Many commercial printers will print at about 1200 dpi, so the more info you can give them...

As for printing at home, I keep all my images at 300 ppi tiff files unless I need them at A3+ and then drop to 240ppi. For canvas, I use an external printer and resize to their requirements to allow for wrapping around the frame etc (you can go quite low on canvas with no obvious loss of quality).

As others have mentioned though, don't get ppi and dpi confused - as I say, my images are stored as 300 PPI files but the lowest res my HP A3+ will do is 600DPI (with options to go 1200 DPI). PPI & DPI often get confused... My A3+ prints are 240PPI printed at 1200DPI for maximum quality.

The CD if for a client not for a print company btw.....

The only reason I am limiting the PPI/dimension of the picture is I have told them I can do them a CD of the image at a lower rate (the Mrs Friends ) based on the fact it will be restricted to 8x6 printable. So anything of decent size they will have to come back. Hence why I wanted it small as possible withouot loosing quality and being able to print much bigger. At 180PPI with the same image printed at 10x* you can really start to tell.

 

[AndySP]

Ok cool - send them an 8x6 at 300PPI with a covering letter stating this is to be used for agreed purposes only - and they need to sign and return a copy. I've done this before with no problem - makes you look more professional and reminds them they can only use for set purpose.

 

[AndySP]

Oh, and put a copy of the doc on the CD - every time they open the image, they'll see the T&C's.

 

[Robbo]

I have head of people putting a certain file on the opens up soon as you put the CD in......any one know of this?

 

[snappingsam]

If you're sending on a CD, send the highest res version you have. Many commercial printers will print at about 1200 dpi, so the more info you can give them...

Andy - you are mixing up dpi and ppi - a very common mistake.

I run a pro photo lab - and I know what I am talking about. You will just increase the processing time - and worse still even degrade the image if the file is too large - you may of heard the term "interpolation". It's normally when people are scaling up a file - but it also effects scaling down - as some data has to be thrown away to create the image - if you have a very oversize file, like a 8x6 at 1200dpi.

If a customer supplied us files at that size we simply would not proceed with the job.

Supply files to your chosen lab at the size (and colourspace) that they ask for. Our suggestion is 300 dpi at the finished print size, in either sRGB or ADOBE98, jpeg quality 10 in Photoshop - 85% in Lightroom.

For your information - a 8"x6" @ 1200ppi would be 197megs and would be capable of a 32"x24" at 300 ppi - or in fact any size of print you could think of!

 

[photoimaging]

Agree with Snapping Sam, we also, as a Pro Lab, ask for files sized to print at 300dpi sRGB or Adobe RGB '98. We've had files in to print 7x5/8x6 at ridiculous dpi's and Mb sizes.

Joan

 

[POAH]

you only need to adjust the dpi when printing. most of the smaller prints are done on machines that work at 300dpi other machines require 256dpi. depends who you send them too. Epson printers like multiples of 180/360dpi for the best print.

 

[snappingsam]

you only need to adjust the dpi when printing

If you are sending to a lab, you need to scale down the file you send them. Some labs insist on exact sizes at 300 dpi - others are a bit more lax.

I once had a 3Gb folder of around 300 files which were to be printed 5"x7"...!

 

[EOS_JD]

If you're sending on a CD, send the highest res version you have. Many commercial printers will print at about 1200 dpi, so the more info you can give them...

As for printing at home, I keep all my images at 300 ppi tiff files unless I need them at A3+ and then drop to 240ppi. For canvas, I use an external printer and resize to their requirements to allow for wrapping around the frame etc (you can go quite low on canvas with no obvious loss of quality).

As others have mentioned though, don't get ppi and dpi confused - as I say, my images are stored as 300 PPI files but the lowest res my HP A3+ will do is 600DPI (with options to go 1200 DPI). PPI & DPI often get confused... My A3+ prints are 240PPI printed at 1200DPI for maximum quality.

What Sam says

Actually the eye can't resolve detail over around 300ppi which is one of the reasons why 300ppi is used.

Regards the 1200dpi as Sam says that is a printer resolution - not the same as image resolution. No labs I know of use such high resolution printers for printing images (I'm not aware of any printers with such a high actual resolution). Commercial printers max is generally 600dpi.

Regards your printer, the ACTUAL resolution believe it or not is a lot less than you think. You are talking about INKJETS - The effective res of an inkjet is much less. An inkjet may sell as a 2880dpi device but is in fact a 2880 drops of ink per inch device. Divide the resolution by the number of ink tanks and you get the effective resolution of the device.

My Epson R2400 has a huge resolution but each drop of ink may cover the same dot on a page so the effective resolution is a lot lower than your 2880dpi. Don't get confused or blinded by these high numbers.

Lets say Epson printing at 2880dpi - With 8 inks that would give 2880/8 = 360pi effective resolution. Or at 1440dpi it would be 180ppi! So you can see why the numbers are grossly over exagerated in actual terms.

So your HP printer will have an effective lowest resolution of 600/No of ink cartridges - Lets say it's 6 - So 100dpi .....- Much lower than you thought!

I also question why you would save as a tif? Shoot RAW export and edit and save as a jpg - no need to further save the jpg and size will be lower therefore speeding everything up.

 

[Robbo]

What Sam says

Actually the eye can't resolve detail over around 300ppi which is one of the reasons why 300ppi is used.

Regards the 1200dpi as Sam says that is a printer resolution - not the same as image resolution. No labs I know of use such high resolution printers for printing images (I'm not aware of any printers with such a high actual resolution). Commercial printers max is generally 600dpi.

Regards your printer, the ACTUAL resolution believe it or not is a lot less than you think. You are talking about INKJETS - The effective res of an inkjet is much less. An inkjet may sell as a 2880dpi device but is in fact a 2880 drops of ink per inch device. Divide the number of ink tanks by the resolution and you get the effective resolution of the device.

My Epson R2400 has a huge resolution but each drop of ink may cover the same dot on a page so the effective resolution is a lot lower than your 2880dpi. Don't get confused or blinded by these high numbers.

Lets say Epson printing at 2880dpi - With 8 inks that would give 2880/8 = 360pi effective resolution. Or at 1440dpi it would be 180ppi! So you can see why the numbers are grossly over exagerated in actual terms.

So your HP printer will have an effective lowest resolution of 600/No of inks.....- Much lower than you think!

I also question why you would save as a tif? Shoot RAW export and edit and save as a jpg - no need to further save the jpg and size will be lower therefore speeding everything up.

Ahhh I like this information!

I save as a tiff from raw. My reasons being, I use raw to correct any 'major' problems and tweak other bits like White balance etc then save as a tiff to carry out my main processing in CS4, a lot of the things I can't do in raw.

Once done I convert to a jpeg for printing /. Client CD.

I always keep the tiff in case any minor adjustment is required, saves going through the full process again. I got a bomb of storage so it's no issue.

 

[EOS_JD]

Ahhh I like this information!

I save as a tiff from raw. My reasons being, I use raw to correct any 'major' problems and tweak other bits like White balance etc then save as a tiff to carry out my main processing in CS4, a lot of the things I can't do in raw.

Once done I convert to a jpeg for printing /. Client CD.

I always keep the tiff in case any minor adjustment is required, saves going through the full process again. I got a bomb of storage so it's no issue.

Not just about storage though - speed too. I've shed loads of storage too but do not save anything in Tif or psd - unless I need to save layers.

Saving a jpg to a jpg does reduce quality but at high quality the compression is minimal and you need to save many times before noticing any IQ reduction.

I don't even think about it and have never had an issue.

 

[Robbo]

ot just about storage though - speed too. I've shed loads of storage too but do not save anything in Tif or psd - unless I need to save layers.

Saving a jpg to a jpg does reduce quality but at high quality the compression is minimal and you need to save many times before noticing any IQ reduction.

I don't even think about it and have never had an issue.

I tend to tinker around quite a lot depending on what kind of image I am working on. I always used jpeg etc until I started to noticed some IQ issues. I suppose I just got into the way I do now due to the pics I mess around with quite a lot

 

[EOS_JD]

So long as I have the RAW images I can create many jpg images all with the same high quality. I rarely save a jpg more then once these days

 

[coldpenguin]

I have head of people putting a certain file on the opens up soon as you put the CD in......any one know of this?

With windows, you can create a file called autorun.inf
Basically a text file which tells windows what to run when it sees it anew.

 

[AndySP]

@snappingsam, it may seem I'm confusing dpi and pip but, if you read my posts in full, you'll see I'm not. I was only suggesting to send a high res file as it gives the printer the best options. I'd recommended an 8x6 at 300ppi and not the 1200ppi/197Mb file you thought I was suggesting - it's not always easy to get facts across when typing (and trying not to get too technical for the OP).

@EOS_JD, I save as tiff as I prefer it this way. I've played with the 'one RAW, many exports' workflow but my old camera didn't allow (a few years old and I had a few dust spots on the sensor I couldn't remove so cloning/tidying needed on regular basis). Now I've upgraded the camera, I might look at the 'one RAW, many jogs routine. But then, most of the publishers I supply insist on tiff - and I'm not trigger happy with the shutter and storage is soooooo cheap these days.

Interesting thoughts on actual inkjet resolution though, must look into that further...

Cheers
Andy

 

[EOS_JD]

Yes Andy I see your point -0 If the client needs a tif then tif it will be

Re the inkjet it's a pretty simple concept really. The manufacturers count drops of ink but it can take many drops of ink to create a specific colour drop on a page. So although 2880 drops of ink were used, only 300dots would be created.

If you print an image at 300dpi on pretty much any image the quality will be superb. At your 600dpi on an inkjet I'd guess the results will be less than great - showing the true dpi is a lot less.

Let me know if you find more.

Cheers
Jim

 

[AndySP]

Hi Jim,

I've noticed the '600dpi' setting isn't great quality. When I first got the printer, I printed the same file at 'normal', 'best' and 'maximum dpi'. The normal is now a blank piece of paper through fading, the best is not looking it's best but the maximum dpi still looks good (they're all hanging in direct sunlight on my office wall to maximise fading etc). I've sat this alongside some 'proper' printers and the print quality compares well. Mine is one of the early HP A3+ beasts and has 3x cartridges with 3x colours/inks per cartridge so I wonder how this would affect the maths and would I be getting a higher dpi on paper in reality. At max/1200dpi setting, I wonder if I'm actually getting a decent resolution...? Now where did I file the manual...

Cheers
Andy