PRINTING!!!

[rdryfoos]

OK--I am confused....its the 72 ppi vs 300ppi , resample  issue.  Should I change the 72 to 300 if I want to print?  I thought that the 72ppi, 100, 200, 300, whatever is controlled by the size of the print.  Will my 8.3 mega pixel image (KAF 8300 sensor) print a 8x10 print the same if I leave the ppi at 72 or change it to 300ppi? 

A bit of history--I am printing out a few images (metal prints) and want the highest resolution I can get--or pretty high....i printed one image at 16x20 and it looks great--Bayphiotio says it showed only slight softening.  But a half hour conversation regarding the best size to print at left me more confused.  They said that the file was set at 72 (PIs native setting) but that the file contained WAY more information than is typical, and changing to 300 would have done nothing.  Is this due to the camera? Is AP different than regulat P.

Any input would be welcome as I am left with trial and error, and at $75 a print, it gets expensive. 

Thanks,
Rodd

[rdryfoos]

OK--so I have upsampled an image from its native # of pixels to higher-from 3294x 2454 to 4500x3352.  This makes the image bigger on the screen, and tells me that I can print a larger print at a respective resolution (say 300ppi).  Here's my question--the image is made bigger by the addition of pixels between pixels.  No real data is added and you can see this by cropping areas in each and zooming.In  a very clever way, PI adds pixels so you don't notice it.  But it is not real data, so can one really maintain 300 dpi by upsampling?  Its not real data so resolution MUST go down--well, meaningful resolution.

So what is better--to upsample and add pixels in this fashionso one can print at 300 ppi,-or to not add pixels (don't upsample) and print the same size print anyway.  In both cases resolution MUST suffer (using the definition of resolution meaning sharpness/clarity....not the # of pixels, which is our NORMAL definition)

Thanks,
Rodd

[pscammp]

rdryfoos,

Not sure what the resolution of your camera would be at 8.3 megapixels but lets use a hypothetical resolution....

Lets say your camera has a resolution of 2500 x 1500 (for example)

If your image file has 72dpi imbedded in it and you send it to the printers, and, they print your image as is, this is what you'd get:-

A print which is 37.7 x 20.8 inches......HUGE and really expensive, and, it will look pretty rubbish unless you stand well away from it.

On the other hand, if your image file at 2500 x 1500 resolution has 300dpi embedded in the file and you printer prints it, you'll get this:-

A print which is 8.3 x 5 inches......And it will look quite nice close up but there may be a little softness to it close up.

If you want to go as far as 600dpi if your printer can do it, this will give you much more detail than the 300dpi option but you will get this:-

A print which is 4.1 x 2.5 inches......The detail in the image close up will be sharp as a knife but you'll need a magnifying glass to see it properly.

If you want a good quality print then the minimum has to be 300dpi, PI has a module for embedding this into the file, 600dpi will be sharper
but the image will be much smaller as a result. Its a trade off between how big you want your image divided by how sharp you want it to look.

Resolution / dpi    =    2500 / 300    =    8.3 inch print

Obviously the higher the resolution your camera is, the bigger the print at a certain dpi you can get away with. Also another option, if you were
to use Drizzle Integration at a factor of x2 then this would double your resolution, thus, doubling the print size you could get at the same dpi.

I recently sent my very first test print to a local printers of M33 set to sRGB and 300 dpi using PI's tools and I got a really nice result back at
9 x 6 inches. Yes it was a little soft compared to the screen but only very slightly but im chuffed as hell with it, so was the MRS   Wooo Hoooo

EDIT: By resampling the image it will look even softer than the original due to interpolation of the pixels but you WILL get a bigger image yes

Hope this helps a bit
Paul

[pscammp]

Hey,

Just seen your new post  !

If you original resolution is 3294x 2454 then at 300dpi you would get an image as is at 10.98 x 8.1 inches

That's bigger than mine    lolol   

Further, if you introduce Drizzle integration into you workflow then your resolution becomes 6588 x 4908, and
you may even get better rounded stars in the bargain. This then would give you a print size of 21 x 16 inches
at 300dpi without resampling at all  ! ! ! 

[rdryfoos]

Hey,

Just seen your new post  !

If you original resolution is 3294x 2454 then at 300dpi you would get an image as is at 10.98 x 8.1 inches

That's bigger than mine    lolol

 

  I printed it at 20x16 and it looks pretty good.  It is for viewing from a distance of 7-8 feet.  Metal print.  What if I supsampled it first.  Attached are 2 crops from an image native #1 and upsampled by 5x (15000 pixels across).  Can you explain what I am looking at.  The upsampled star ius round at any zoom, where as the not upsampled star is pixelated almost at any zoom.  Also the pixels look smaller in the upsampled one.  How will this relate to printing?

[rdryfoos]

They must have changed things on the forum--I can't view the images the same way as I could before.  My point is missed.  at least on my computer.

[rdryfoos]

So whats better--upsampling and printing at 300 dpi and it will be softer due to upsampleing--or not upsampling and printing bigger so it will be softer iue to the size?

[macnmotion]

Either way you're upsampling. If you print larger, the printer driver is doing the upsampling for you. I've always found that handling any upsampling yourself yields better results.

Not all upsampling is created equal. Some algorithms are better, for instance fractal algorithms. Any upsampling adds "fake" data so upsampling is a personal choice, but if you do choose to upsample it makes sense to use the best method available.