File size & printing

[cliveanne]

I have images I want to print on A4. The original image files are 4288 x 3216 pixels. I also have a copy or copies at 1000 x 750p or 900 x 675p Does the file size matter? I'm quite new to this printing game. Any help would be useful.
Thank you in advance

[Colin Southern]

Hi Clive,

Normally one would run with the highest resolution file available (there's normally no disadvantage, whereas there are likely to be disadvantage to printing with lower resolution files). In this case the 4288 x 3216 image will give you a resolution of around 366PPI, which will be just fine.

[arith]

Hi Peter; the more pixels the better. I've got an interpolation program that uses the more accurate Mitchell method and any I may want to enlarge and print I do first time round to save the bother later. It makes absolutely no difference to the quality of prints around A4 or smaller.

[DanK]

I'm also a relative novice at printing. However, you might want to check out this. The end suggests that in some cases, you would want to downsample for small prints. (Read the very end, along with the attached graphic).

I've avoided all of this by printing from Lightroom's print module, which takes care of this. All you have to do is specify the DPI you want for the printer and the print size. As long as there are enough pixels, it does the rest for you. So far, printing mostly 8*10 (~A4) and smaller, the results have been very good.

[Geoff F]

Just a couple of extra thoughts, Peter. By A4 size, do you mean a print area which is full A4 or are you using A4 paper and producing a print which will have a plain unprinted border. Which would reduce the actual print area; say something around 250 mm on the long side.

Also, are you printing yourself or going to a printing company?

Some printing companies insist on a photo resolution of 300 pixels per inch. Although in reality, with home printing you can usually work will a bit less without seeing any problems. 200 ppi usually works fine and you may still be OK as low as 150 ppi. It depends on the paper and printer, etc; also the actual content of the photo can have some impact.

As Colin said 4,000 pixels, or larger, is more than sufficient for full size A4 prints. But 1,000 pixels would only give 83 ppi which is far too low.

Basically, it is just a case of doing the maths. Whether you resize the image to obtain a 'perfect, number of pixels or just let the printer do it automatically is up to you. But in most cases an auto adjustment works fine. Although if printing at a substantially reduced size I often prefer to be in charge of the reduction method and, possibly, do a little resharpening of the image before printing.

[cliveanne]

I'm also a relative novice at printing. However, you might want to check out this. The end suggests that in some cases, you would want to downsample for small prints. (Read the very end, along with the attached graphic).

I've avoided all of this by printing from Lightroom's print module, which takes care of this. All you have to do is specify the DPI you want for the printer and the print size. As long as there are enough pixels, it does the rest for you. So far, printing mostly 8*10 (~A4) and smaller, the results have been very good.

Thanks for the link DanK. I checked the link, only to find the whole site is down I'll look in there again later)

[cliveanne]

Thanks for the info guys. Your input is appreciated.
I will have a plain white border & use my own printer (Epson Stylus Office Bx 305FW) on Fujifilm glossy brilliant 190g/m² . I have printed in the past & always from 4288p x 3216p. I normally reduce my file sizes to 1000p x 750p unless cropped to save space on my laptop. I will reduce to 900p x 675p for posting on forums & the like (some sites ask for even smaller files).
I seldom print images, but since starting a (second) photo group with our local U3A (University of the Third Age), the printed image is easier to pass around for discussion. It also saves carrying the laptop around & from possible accidental damage.

I have an old Gateway 'puter upstairs with a spare 500Gb drive sitting inside it. It was installed by my son a few years ago. The idea is to remove the drive & use it as an image storage facility. I can then keep the laptop clean & lean. Well, that is the idea anyway
Cheers

[casper]

hi Peter. you are correct to print with a border. 4288 x 3216px is a ratio of 4:3, while A4 paper is 297 x 210mm (about 4:2.8). For this reason, you have to print with some selvedge to maintain the aspect ratio and not distort the image. If you printed A4 borderless, you would either need to crop the short edge or stretch the long edge by about 6% to fill the sheet. Maximum size with a border all around would be about 276 x 207mm. I would suggest a good size for A4 would be something like 254 x 190.5mm (10" x 7 1/2"). Printing landscape, this would give borders 9.5mm (3/8") top and bottom, and 21.5mm (27/32") left and right. Hope this helps.

[Geoff F]

Printing A4 paper with an equal all round border is easy, Peter. Providing you get the maths correct.

Let's say we want a 1 ins all round edge. So the print size becomes 9.75 x 6.25 ins (2925 x 1875 pixels at 300 ppi). I resize the image so one side fits the requirement and the other is fractionally long. Then I crop that side to suit and away we go!

This does depend on having suitable software to crop to exact sizes (inches or software) but isn't difficult. I suppose you could work out a crop ratio as well.

[cliveanne]

Noel & Geoff F, Thanks for the info. I did try a borderless A 4 on my old printer a few years back, I could not see what was wrong with it. There was something, but I could not put my finger on it. Anyway, I did not like the result, so anything I print now will have a border.

I'm saving any advice I get into my "Photo notebook" so when we meet at U3A, I will have facts & figures available.
Thanks again.
P.

[Macmahon]

Peter
To get a handle on what the down-sampling and up-sampling is, and why or whether you should bother, have a look at the DPI vs PPI question on http://fromcameratoprint.com/Referred%20pages/FAQs.html.
The fundamental idea is easy: in the end, you have to send an image pixel to a printer dot. The challenge arises because very few images have the exact number of pixels to match the number of dots in your print, so somehow you have to arrange for the information in the image pixels to be redistributed - that's resampling. To know how much and what kind of resampling the size of the photo and the required dot pitch need to be known. It's all explained in the above link.
Cheers
Tim

[cliveanne]

Peter
To get a handle on what the down-sampling and up-sampling is, and why or whether you should bother, have a look at the DPI vs PPI question on http://fromcameratoprint.com/Referred%20pages/FAQs.html.
The fundamental idea is easy: in the end, you have to send an image pixel to a printer dot. The challenge arises because very few images have the exact number of pixels to match the number of dots in your print, so somehow you have to arrange for the information in the image pixels to be redistributed - that's resampling. To know how much and what kind of resampling the size of the photo and the required dot pitch need to be known. It's all explained in the above link.
Cheers
Tim

That was interesting reading Tim. Thank you.
I have saved the link in my bookmarks
Cheers.
P.