[barondla]

Want to make a 16x20 enlargement from Pentax 645Z file. Only place close is a Walmart using an Epson wide format printer. Do I sharpen the file or does the Walmart/Epson software do this automatically? If I have to sharpen, what settings get me in the ballpark?

Thanks,
barondla

[pschlute]

Want to make a 16x20 enlargement from Pentax 645Z file. Only place close is a Walmart using an Epson wide format printer. Do I sharpen the file or does the Walmart/Epson software do this automatically? If I have to sharpen, what settings get me in the ballpark?

Thanks,
barondla

I regularly using a commercial printing company to print K1 images. Printing requires more sharpening than screen viewing. As a rule of thumb I use twice the sharpening settings for printing than for screen. You should sharpen your own images before sending them.

Do Walmart tell you what size image in pixels they require for your specified print size ? That will depend on what ppi they require.

[texandrews]

Gosh, Walmart....If I had a gun to my head to force me to print there I guess I's want to talk to the person running the machine and find out if they have any idea about what they are doing.

I would think that for a small print like this your normal sharpening would be fine, sharpened for print of course.

[btnapa]

Do I sharpen files for Epson wide format printer?

I had an Epson 44" printer which I sold last year. I always made test prints before I made a large print. If you decided to make a test print, create a new 16x20 blank page (300 dpi, RGB) and drop an 8x10 of the same file with different treatments (sharpening, exposure, etc.) into the 16x20 and have them print to see which version looks good. Make sure your file is RGB and not CMYK. The Epson driver does a great job of converting RGB to CMYK which is what the printer uses. If the lab provides a profile for their printer, use it as it gives you a better idea of how the print is going to look in advance.

I printed plenty of files from my K3, K5IIs and K1 and they all looked fantastic. Your 645Z is going to be a cut above. A few times I wanted to see how far I could push the K1 files and printed some 40"x60" prints from a single file and they looked amazing. So your 645Z prints are going to look even better.

BTW, I have used the COSTCO lab for a few prints (before I bought my Epson printer) and they did a great job. So try them out soon as I read the other day that they are closing all their photo labs sometimes in February. They use a 24" Epson printer for all their large in-house prints. Prices are super cheap too.

Good luck with the printing.

Cheers,
Boris

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Last edited by btnapa; 01-15-2021 at 04:09 PM. Reason: more text

[Fenwoodian]

I regularly using a commercial printing company to print K1 images. Printing requires more sharpening than screen viewing. As a rule of thumb I use twice the sharpening settings for printing than for screen. You should sharpen your own images before sending them.

Do Walmart tell you what size image in pixels they require for your specified print size ? That will depend on what ppi they require.

Wonderful advice! I have my own large format Epson printer and can not add anything to this authoritative statement, other than the optimum ppi for large format Epson printers is 360

[Chapel]

Hi Boris, not to hijack the thread but I just got an Epson 44" printer for a song. I have no idea what resolution to set for my 645z prints. The largest so far is 12x16. Do I change the ppi from 300 to 240 or lower to make larger prints?
Thanks
Greg

[barondla]

Gosh, Walmart....If I had a gun to my head to force me to print there I guess I's want to talk to the person running the machine and find out if they have any idea about what they are doing.

I would think that for a small print like this your normal sharpening would be fine, sharpened for print of course.

They don't have much control over the process. They the turn printer on in the morning and off at closing and keep it full of paper and ink. Everything is calibrated and controlled by Fujifilm ( Costco is/was also serviced by Fujifilm).

Living in the boonies, Walmart is all that's available. This is a test to see what a decent size enlargement looks like. It beats waiting days to get an enlargement. Anything important will be printed elsewhere.

Thanks,
barondla

[AstroDave]

I can't vouch for Walmart (although I did use them to print my 8x10s for a photo class back in 2008 or so, and they were fine), but I use Walgreens (also here in the boonies) and they are generally quite good, too (again, only up to 8x10). I used Staples (a stationary store) for a couple of 12x18s on foam core and they look good and have held up nicely for ~10 years, too.

[pschlute]

Hi Boris, not to hijack the thread but I just got an Epson 44" printer for a song. I have no idea what resolution to set for my 645z prints. The largest so far is 12x16. Do I change the ppi from 300 to 240 or lower to make larger prints?
Thanks
Greg

When you prepare an image for printing, there are three elements to consider : Document size in inches/cm; Pixel dimensions HxW; Pixels per Inch (ppi). These are all points of the same triangle. You cannot change one without affecting at least one other. So changing the ppi may make the document size larger (keeping the pixel dimension the same), or it may simply downsample the image (less pixels) and keep the document size the same. You need to check your settings when you change the image size.

300 ppi is generally accepted as a good pixel resolution to use. The commercial printer I use requires images to be submitted at 300ppi. If you lower your ppi to get a larger image you may be compromising on image quality (although 300 to 240 is not much). Up-sampling an image may be a better proposition.

Your 645z produces a file with pixel dimensions of 8256x6192. At 300ppi that means you can comfortably print up to 27.5 x 20.6 inches at top quality without needing to upsample or reduce the ppi.

Editing this to just add that my post here is only mentioning ppi (pixels per inch), which is a property of the digital image file. Please do not confuse this with dpi (dots per inch) which is a property of the printer. The two terms are very different.

[dms]

Epson is best to use 180 dpi, 240 dpi, 360 dpi, etc. not 300 dpi.

---------- Post added 01-15-21 at 10:34 PM ----------

Not everyone agrees that sharpening is a good thing. I don't usually sharpen for prints, except when the resolution is pretty low--e.g., cropped a lot. In any event better to sharpen less than to over do it and have halo's.

[biz-engineer]

Epson is Inkjet print tech. Inkjet printing is sharper than C-prints, nevertheless, a bit of contrast boost and sharpening helps.

Now how to know how much sharpening to apply?

The first step is to use zoom factor so that the features of a photo seen on monitor have the same physical size as they would on the print.
The second step is to know the max limit of sharpening that makes details pop without creating artifacts:
-> increase sharpening until you start seeing halos at edges, stop the slider there
-> then decrease sharpening from there until you see no fake halos (on monitor), that's the optimal sharpening setting.

[Chapel]

Thanks for help.
Greg

[TonyW]

Hi Boris, not to hijack the thread but I just got an Epson 44" printer for a song. I have no idea what resolution to set for my 645z prints. The largest so far is 12x16. Do I change the ppi from 300 to 240 or lower to make larger prints?
Thanks
Greg

For the Epson printers you would set your image resolution to 360, 720 or even 1440 PPI

These are the requirements for the print driver as reported to the OS. To get the optimal from your image data will usually require you to resample the image to one of the above figures in your editing software before sending to print. If you use the print driver it will resample your image data to its native requirements using algorithms designed for speed (Nearest Neighbour or similar). Superior algorithms are used in printing applications such as PS, LR and Qimage.

If native resolution is below 360 ppi then resample to 360 ppi.

If the resolution of your image is over 360ppi but under 720 then resample to 720ppi.

If over 720 ppi then you may see some benefits to sample to 1440

The next thing you need to consider is quality setting which is quoted as DPI by the manufacturer (DPI, dots per inch or Droplets per inch). In many cases the printer driver will specify a setting such as Draft, Fine, Super fine and or a series of numbers representing the print 'quality'

[btnapa]

Hi Boris, not to hijack the thread but I just got an Epson 44" printer for a song. I have no idea what resolution to set for my 645z prints. The largest so far is 12x16. Do I change the ppi from 300 to 240 or lower to make larger prints?
Thanks
Greg

Hi Greg,

Since I had the printer for a number of year. I got to experiment a lot with the resolution settings. Most people would say that for larger prints you do not need as much ppi/dpi. That is somewhat true. For my larger prints above 24"x36" I would go down to 240 or even 180. For most part you do not see a noticeable quality drop. However, I did run some test large prints at 180 and 300. I did notice a quality difference. 645Z has a set resolution which would allow you to prints at 300 dpi up to a certain size. I do not remember the math for that. For argument's sake, let's say that size is 18"x24" (3x4 aspect ratio) at 300 dpi. If you print a 42"x56" and you set your size in Photoshop for that particular size, then Photohop will interpolate your image resolution to give you that bigger size. This effectively reduces your resolution/clarity. In a practical level, you do not see much degradation if any for that size increase. I have gone down to 100 dpi/ppi for my K3 for some trade show posters 42" wide x 96" tall with fantastic quality prints. You can get perfectly acceptable prints from really low resolution files. There is a big exception to this rule, If you print for sale as art prints, I would say print at minimum of 300dpi. If you send your work to a pro gallery as "museum quality" prints, they have to be minimum 300dpi.

The other factor that effects the final look of the prints is the resolution the printer uses. I printed at 720 dots per inch as the speed is reasonable. You can go up to 1440 or 2880. Again I did see a difference between 720 and 1440 print but the time trade off was not worth it. If I remember correctly, the 1440 took almost 3-4 times longer to print than the 720. It has been a while since I last printed so pardon me if I did not get the terminology right.

I did push my K1 files to the limit and they gave me very nice 40"x60" prints. 645Z is a beast and should give you sellable 42x56" (40x60) prints easily.

Maintaining an Epson printer and make sure it prints. That is a whole different discussion. I cleaned (purged) the heads a lot. I could not afford to do that with expensive Epson inks. So I found a dealer in California who sold aftermarket ink at 1/5 the cost of Epson inks. Colors were indistinguishable from Epson original inks. At that point I did not care if I wasted a lot of ink purging heads and keeping the printer. You have to print often as Espon does not like to sit idle (heads dry up).

Hope my input helped you some.

Cheers,
Boris

[TonyW]

You may send image data to your printer at whatever PPI you need to make a particular print size, 10 ppi, 45 ppi 100 ppi 240 ppi 300 ppi.

But your printer will not use anything other than its native resolution and in every case above the print driver will interpolate using Nearest Neighbour algorithm to 360 PPI if it is Epson. Canon, HP, Fuji, Noritsu printers will also resample to their native resolution which is 300 ppi, 600 ppi or 1200 ppi.

So best practice is to first send data at the printers declared PPI 360 for Epson and do not throw data away if you require optimal quality.

Your 645z produces a native file of 8256 x 6192 pixels

Using the Epson printers native resolution @360 PPI will give you a print size of 22.9" x 17.2" for Canon at its native resolution @300 PPI the print would be a little larger 27.5" x 20.6". It is a trivial matter in PS or Lightroom to upress your print size 200 - 300% and maintain high quality but remember to also resample to printers native resolution for optimal results. Should you wish to go larger then you may want to look at some of the newer stand alone programs such as Topaz A1 Gigapixel.

Larger prints can of course be made and viewing distance should be taken into account as the further away you view the less detail you will see and PPI requirements will be lower to perceive continuous tone. However your printer does not know this and it will still interpolate to 360 ppi 😉