printing sizes and sharpness of images

[Ms Monny]

After getting one of my images printed on a 20x16 for the first time, I was thrown into the world of 'printing sizes'. I searched the net trying to find what the largest size I could print from my 18mp camera.

A few sites differed with their info ... some said 10x8 was optimal but anything bigger will not look as good (unless super sharp image), others, as epicaricacy mentioned, said 20x16 is great and beyond!!

So, I am wondering this....how do photographers get to print LARGE poster sized images (larger than 20x30)? Are their cameras 40mp? Do they only use film?

Also, how can I ensure that my images are super, super sharp to get them at a 20x16 or 20x30? (yes, using a tripod etc)

I read that you do this ....

1. a small sharpen at the RAW converting stage (Lr or Camera Raw) of 40 or so
2. when in Ps you use an USM to sharpen to how you like
3. convert the image size (which may make the image a bit soft)
4. use a USM at a small % and only .5 pixel to bring the sharpness back.

This, they say, will ensure super sharpness on the image!

What are you thoughts and your process??

[jjphoto]

Sharpness starts when you take the picture.

If you use a lens with poor resolution, hand held, then you will always be fighting to get a sharp image. Alternatively if you take all the required steps to get a high resolution image then it will always be easier to get a sharp looking print at the end of it.

Test your lenses and figure out which ones are sharp and which ones aren't. This is a first step that everyone should know. Use a tripod, use mirror lockup, focus with Live View, use the lens at it's optimum setting, use a low ISO etc etc. These things will make a bigger difference than simply sharpening an image which was poor to start with.

[Ms Monny]

thanks John. Testing the lens is something I didn't really know about, and I will definately do it! I have found when doing all the correct things regarding tripod etc, my lens at certain apertures is NOT SHARP and it frustrates me as there is nothing else I can do to make the image sharp.

I also actually want to know about the printing side of things.

"Also, how can I ensure that my images are super, super sharp to get them at a 20x16 or 20x30? (yes, using a tripod etc)"... using a tripod, etc meant stable tripod, mirror lock-up, live view, low ISO etc but other than that, what other steps do I take to get super sharp images (in PP)?

[nwhc]

I have had some of mine printed 20x30 from my old 40D 10-20 sigma days they look great, and that wasn't 18mp
Yes you can see a bit of pixelation when you stick your nose on them but from a meter or 2 back they are fine.

[Warbler]

If you're going to print larger than the native pixel dimensions of your camera, then you're going to have to upsize the image by extrapolating it in some form of software. That will always have an effect on the quality of the image. As John said above, starting with the best possible image helps. Image content also has an effect. You don't always want tack-sharp prints (the girls will tell you this). For images that you do want tack-sharp, you'll need to find a method that works for you. I've seen images taken at 2.1MP that have been printed at 20x30 inches after going through Genuine Fractals. They looked good. I've also seen images printed at 16x20 inches from 12MP cameras that looked crap. Sorry to throw more mud in the water for you.

Cheers,Tim

[Ms Monny]

hmmm, ok......well, I will definately start with testing my lenses! Then I guess I will go from there. Thanks for your comments Tim and nwhc!

[ameerat42]

Monika. Here's a start. Use Photoshop or its ilk and do an Image Size to find out what the "native" size of your image is.

It might say something like 60cm x 40cm and it may have a "Resolution" figure of say 180 pixels per inch.

Click on the Magnifier tool and then select Actual Pixels to view it on your screen at full size. Scroll about and see what it looks like.
(ie, pixel peep.)

Use the size and translate the "pixels per inch" into "dots per inch". Print a critical portion of the image at this size and go from there.

There is such variation in getting an image from camera to print that a thousand people waving arms will still not necessarily fit the bill.
Am.

Oh, Warbler's post. Of course, a lot depends on what sort of camera you're starting off with, but that's not an issue here.

[JM Tran]

Hi Monika, 18MP is great for printing beyond that, you will be fine at 45x30 inch too

A nice sharp photo on a big print depends on things like shutter speed to avoid the shakes, an ISO level to prevent much loss of details ie. you would not enlarge an image to such size if it has been shot at ISO6400 for example. For post processing the right amount of sharpness used is important too.

I have had a 10MP shot from an old 40D years ago blown to 45x30 inch - it looked great! But this was viewing it at 1 or 2 meters away, so viewing distance is something to consider.

[mikec]

Monika the thing to understand with printing is DPI and viewing distance.

A quick and simple explaination. For small prints that are viewed very closely, like a 4x6, you should probably be printing at 200 to 300 DPI.

For a larger print that you could be veiwing say 1 to 3 meters away, you could easily drop your DPI, say 150 to 200 and not notice the difference. Since you won't be up close looking at the printed surface.

For something bigger again, viewing from 3 to 5 meters I'd go down less but would probably do a small test area before commiting to an entire print.

If you get up close to a street billboard you will notice that the print resolution isn't actually great. It's just that at such a distance you can't see the detail.

To quickly see what DPI you images will print at, open them in photoshop and resize the image to be the printed size, just ensure it doesn't scale the image. I can't remember the exact name of the option you need to tick. After this you will see what DPI your file will print at. Most of the you'll have a lot of room for the DPI.

As far as sharpness, I find prints generally just needed an extra boost of sharpness from what you need on the screen. But I think it depends on monitor and printer set up. Testing and experience are best here since there isn't an exact answer as it also depends on the paper stock you are using.

Cheers,

[Ms Monny]

Thanks JM and Mike.

Mike, I always put all my images at 300ppi, no matter if I am printing a 6x4 or 20x16. I am worried that if I have a low ppi for larger images, that they will look pixellated!

Regarding the sharpening....well, yes, experience is the key! I don't print at home, but through a lab in the city that I can go in and talk to and have a relationship with. I am in the process of testing the colour calibration of my computer with some printed images. I've only used them for black and white images, and the tone looked good and so did the sharpness.

Thanks for your comments.

[ricktas]

Lots of great information here, but one thing is missing. The larger we print the bigger the viewing distance. Print at 4 x 6 and we usually view them by holding them in our hands, even in an album, and look at the photos. Take a 4 x 6 and view it from the other side of a room and you may even have an issue identifying what the subject is, let alone if the photo is sharp.

BIG prints need to be viewed at a different distance to a 4 x 6,. Try viewing a 60 inch wide print while it is sitting on your lap. To fully appreciate it, you need a bit of distance between yourself and the subject. Thus the level of sharpening needs to take into account both the size of the print and the viewing distance that it will most often be viewed at.

Here is an example of sharpening optimal levels based on viewing distance and print resolution

Image viewed from 1 metre @300 PPI should be sharpened at a radius of around 4.70 pixels radius. The same image at 2 metres should be sharpened at around 9.45 pixel radius.

I got this information from a printer friend of mine who uses a calculation system to sharpen HUGE prints.

So think about not only the size of your print, but the distance it will be viewed at, before determining a sharpening methodology. To help you on your way there is a sharpening radius estimator (and other good info on the subject) HERE

[Ms Monny]

oh!! so even the pixels radius needs to change?? That makes sense! So if I print at 20x30 and sell it, I would have to presume they are viewing from 'x' distance?

Just had a quick peek at the link....great info! Will read indepth tomorrow (need to go to bed!).

Thanks for the great advice....as well as all the other great advice. I've learnt alot!

[cupic]

The thing is with large print ,is how near/far you are?
With prints of 20X30 you are not going to be viewing it @ 6",but to enjoy it across the room
With dpi @ 150 its going to be big where as the dpi of 300/600 is going to be a nice 6X4 depending on resolution of the camera


cheers

[Eberbachl]

Look at an image printed at 1 pixel per inch from far enough away and it's going to look great.

[Ms Monny]

Well, I might just put $25 towards a print for me and try the lesser ppi and see how it goes! This is so interesting...who would have thought this would also make a difference!

[agb]

Cambridge in colour has a calculator for pixel radius, ppi, and viewing distance, at the end of this http://www.cambridgeincolour.com/tut...sharpening.htm

[Ms Monny]

Thanks Graham....another great read that I will get to later, from Cambridgeincolour!! This is fantastic.....just what I was after!! As silly as it sounds, I really didn't know much how the radius affected the outcome for screen or print, nor did I really understand Threshold!!

[agb]

Have you come across Damien Symonds articles ? Might also be worth a read.
http://www.damiensymonds.com.au/art_enlarge.html
http://damiensymonds.blogspot.com.au...izing-and.html
http://damiensymonds.blogspot.com.au...all-first.html

[arthurking83]

Well, I might just put $25 towards a print for me and try the lesser ppi and see how it goes! This is so interesting...who would have thought this would also make a difference!

I wouldn't place any importance on PPI, DPI, PPG or GST(hang on, you need to factor GST! ) .. but anyhow, just supply the printer with the highest best quality file, in whatever format they prefer.

I've printed only one HQ large sized print, and it was printed at 30x17", as that was the ratio I supplied the image file to the printer.
He wanted a tiff file of a minimum file size and in 16bit tiff format for best quality, but jpg would have sufficed).
From there, he did all the necessary file manipulation work. The only caveat here is that I physically took the file in on a USB drive and he transferred it to his machines.
If you are doing all this over the net, then tiff may not be an ideal format to work with.

My sis has also printed 30" version of one of my images which was captured with the D70s .. at 6Mp .. you do the math.
I've seen the print, see it all the time actually, and the 'sharpness' factor of the print, is never really in question when viewing the image.

I don't do any special output sharpening or anything like that, I only use USM on my raw files as I disable in camera sharpening, and USM any areas that need it, rather than apply a general all round USM, or any other sharpen routine.

I suppose the printer will explain to you the need for any image finalization(as mine did) and whether your file should be set with this or that processing step.

The printer I used(Prism Imaging), explained to me, that all he wanted was the highest quality file and he did all the prep work based on what he needed to do to the file before printing.
A high quality printing service should be this way inclined(IMHO).

for general purpose prints, I've used Officeworks(because they were convenient, for a 200 batch job for my mum. These were scans tho and all at 6x4 sizes.
All these scanned files were large sized 3000x2000 jpg format files and no pre prep work was done to them in terms of setting DPI. The Kiosk machine did all the relevant work for them.
They all turned out perfect(for mum).

File sizes are really only important if you are bandwidth limited for uploading files to your printer.
Output sharpening and PPI/DPI is really only important if you are doing your own print work.(on your physical printer, not outsourced to a pro lab).

If I can get a high quality 20x30 print from a 6Mp camera(remember tiff file was supplied to the lab) then I'm sure you won't need to stress about a HQ print from your 18Mp camera!

[Ms Monny]

hmmm, food for thought! I am sending to a printer (Atkins in Adelaide - highly reputable and I can pop in to see them if needed) via online, and wont be printing myself. I love the fact that your printer can use the TIFF and do what needs to be done (sharpening etc) to the image before HE prints it. Yes, this should be the norm!

All great info! Thanks everyone!