re-sampling images before printing

im slightly confused when it comes to re-sampling images before one goes to print.

 

I'm currenty working on my D700 shooting in RAW (native resolution 4256 by 2832), and i print on my Epson 3800

where i've been told that 360dpi is the best to print at.

 

Question is, i find myself mostly printing A3+ size images (13 by 19 inches). When i go to print, do i need to

change settings in my IMAGE SIZE menu? i tend to just go to page set-up, select the page size.. then i go to

print with preview select everything and click on scale to fit media...

 

am i supposed to do something else in IMAGE SIZE while in photoshop for better results? i thought maybe i should

open up image size, then in document size - punch in 13by19 inch...... and go from there... perhaps when i do

that i need to select Bicubic Sharper...

 

can someone confirm whether im on the right track....? whether i can just go to print preview and select fit to

media.. keeping my image at 360dpi... or whether i HAVE to go to IMAGE SIZE, punch in the image size that im

after and click on bicubic sharper... (been told to always click that whether i upscale or down-scale image)

I've had issues with aliasing when I leave the rescaling to my 3800 (the Scale to Fit option). I now generally rescale to the proper size in Photoshop, print, and then discard the rescaled image (either use the history palette to 'undo' the resize, or don't save the rescaled image if that's all I've done to it). If you rescale within Photoshop you should select the appropriate rescaling algorithm- there's one for upsizing and another for downsizing (among others).

You can send whatever you want to the printer and it will resample the image to it's native resolution (720dpi). However, if you rescale in PS, you will get better results. The printer driver is not good at translating vectors such as circles, arcs, and diagonal lines...it will make stepped edges.

 

PS will fill the steps and make sharper edges. Use bicubic smoother for upsizing - apply sharpening to the upsized image.

 

Use bicubic sharper when down sizing.

According to Jeff Schewe, Greg Gorman ,and Mac Holbert at the Epson Print Academy seminar a couple of weeks ago:

 

You should be fine by not resampling your images as long as the file you send it has greater than 180ppi resolution.

 

So, open the photo in Photoshop (you are working in PsCS3 as I recall). Go Image >image Size and turn off (by unchecking) Resample Photo. this links the Width, Height and Resolution settings in Document Size.

 

Now adjust the height or width to the size you want and as long as the Resolution is above 180 pixels/inch you should not see a reduction in image quality. Even the representative from Genuine Fractals parent company acknowledged this. But if f you go below 180 then that is the time to employ Genuine Fractals or other methods of resolution interpolation.

 

Now turn the Resample Image tool back on.

The resampling filter within the printer is better than what is in ps. Does a great job.

ellis, i just tried out what you suggest on an image.... i uncheck the resample image box.. punch in 13 by 19 inch in document size.. and my resolution drops down to 140........... from what i know, i need to be printing at 360 for my epson.. this is not making sense :(

IMO trust the printer..except when making tiny prints (eg 2" sq).

>>> from what i know, i need to be printing at 360 for my epson..

 

Nah... Anything above 180 or so works great...

And the CTO of ImagePrint said >150 in a technical white paper.

fair enough, but when i do what ellis suggested i do... my resolution changes to 140.. not even 180 !

"from what i know, i need to be printing at 360 for my epson.. this is not making sense :("

 

What you know ain't necessarily so

 

Why don't you go ahead and make some prints and let us know the results?

thank you ellis... should i still go ahead and print even if im getting a resolution UNDER 180 when i re-sample as you had suggested..? you said anything over 180 is fine..... but im getting 140 when i re-sample the way you instructed :)

Frankly I don't bother. John is right, trust the printer. I have a complete HP set-up and do only 8x10 working prints for myself, the rest goes off to a prolab. I never had any problems and in fact the 8x10's I do myself are really very good, in colour and even more importantly in b&w as well. So no resampling here.

 

Not everything has to be (made) complicated.

"but im getting 140 when i re-sample the way you instructed :)"

 

If you get 140 ppi and you're printing a 13 x 19, then your image is only 1820 x 2660 pixels (13x140 by 19x140). Did you crop it a lot?

no cropping at all...

 

\i bourght it in from camera raw... camera's native resolution (my D700) and went straight into what ellis suggested, just to see what the steps are... and thats what happened.... :(

i just re-checked, it actually comes up to 149. xxxxx...

What does it say in the Image Size window at the top under "Pixel dimensions: Width and Height"?

aha, ok i thnk we're on to something alan - my wrong... i've just tried to punch in 13 by 19inches in the pixel size... after i UNCHECK resample image.... when i punch in width, 13 works fine.. but when i go to punch in 19 inches for height.. the width changes to 28.554 inches....

 

sorry, didnt realize this was happening... how do i do it so that i punch in exactly what i want?

You can't get exactly 13 x 19 inches when you resize a full resolution image because 13 x 19 isn't the same aspect ratio as the sensor which is 2:3. You don't want to put a number into both width and height. If your image is a vertical image ("portrait orientation") and you type in 13 into the width, the height will automatically display it's dimension which should be about 19.5 inches or so. Once you've resized like this you will have to go back and crop to 13 x 19. This is all assuming you have cropped or resised the image earlier.

 

You didn't answer about what the pixel dimensions are when your in the Image Size window.

great, thank you so much - finally got it and understand it :) phew

 

my last question is - a while back i read an article stating that whether i upsize or downsize image to ALWAYS go

with image sharper... while other schools of thought say that when i upsize to go with bicubic smoother and

downsize... to go with sharper.. any thoughts on this?

ONE more question - what about if i find myself in a situation where the client needs an image on CD to then send out to publications.... im doing a portrait next week for a client .. who needs the image on a CD, to then just send out to random publications that request it (public figure) as i dont know the size etc that the image will be set at.... is there a general setting i should set IMAGE SIZE at....? how should i go about that?

I did this test a while back by sending file sizes of different resolutions to the printer. The files that were interpolated to 240 or 360 had no roughness to straight lines......images that were sent at off sizes like 207 and 289 had a rough look to fine lines.

 

So, I always interpolate the image to 240dpi or 360dpi prior to sending to the printer, and I've found better results. YMMV.

try printing with Qimage. All that resampling...too many numbers to keep in my head.

Very interesting. This is just to mark it. Will red when I have time. Karl

Here is a handy little tool for determining your printers optimum native resolution by using your eyeballs. Just print it out, making no changes in size or resolution and examine with a magnifying glass or a loupe.<br><br>

 

 

 

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