How to make a 30X45" print resolution test on a 12X18" print?

I want to see how well my Fuji XT20 will print at 24X36 and 30X45 but the print cost is more than I want to spend. I know there is a way to create these two image sizes but print just a portion of each of them on a 12X18" print. I just want to see how the resolution/details hold up and to ensure that I see no pixelization. 12X18" will demonstrate that. I created each of the two larger sized images in Photoshop but when I set up a print order at Adorama, since the aspect ratio is the same for all sizes, they just showed that everything was great to print at 12X18. How would I set this up using an online order process? Also, in general terms, when I output for print, I usually just use the image size box in PS to enlarge the image to the final print size and adjust the dpi to 300. Is that what most people do? Thanks, Bob

Best to create the image as it would be printed (that size, resolution), the crop an area 12x18 or whatever size you wish with important detail you'll want to examine WITHOUT resampling and send that off.

You can probably get away with as little as 180-200PPI for the output.

Thanks Dog, I'll do that.

Thanks for the help.

Best to create the image as it would be printed (that size, resolution), the crop an area 12x18 or whatever size you wish with important detail you'll want to examine WITHOUT resampling and send that off.

You can probably get away with as little as 180-200PPI for the output.

 

Dog,

 

I went into PS and cropped the most detailed portion of each image, the 24X26 and 30X45 to 12X18. So I ended up with a nice cropped portion that measured 12X18. But in each instance, the resolution of the final 12X18 remained at 300dpi. How do I take that final step to make sure, as I assume is going to be the case, that the dpi resolution will fall in relation to the cropped percentage of the original size? Or are my final 12X18 image files correct as they are?

 

Thanks, Bob

Use the same resolution in the cropped version that you would use in the final, large print.

Great. Then I'm all set.

Thanks all for the help.

Bob

Make sure when you resize your image in Photoshop to 30x45" you uncheck the option box to resize the image. You then choose a fixed crop box at the specific size in inches. Photoshop should then do it correctly.

 

If 'Resize' is left checked Photoshop will just rescale to whatever size you indicated at the default dpi (usually 300) and you will get a 30x45 at 300 dpi with massive amounts of fake information (interpolated) added. You do not want this. The lab should be doing this, especially if it's a Lambda / LightJet RA4 type printer, which is the most common type for online enlargements. They should also have no problem with a 30-45" file from a 24mb capture provided it's sharp and artifact free.

Thanks Scott,

 

What I do is go into the 'file size' menu of the the native file and change the length and width to the desired size, set the dpi to 300 and accept the Photoshop suggestion of using bicubic smoother. I'm not at my computer now but I don't think I hit any other checkboxes. I do know that when I look at the resultant larger file, it seems very clean and detailed at 100%. I have not seen pixelization at 30X45. I will have to check what I do, or don't do, with the 'Resize' checkbox.

Thanks,

Bob

Edited October 25, 2018 by bob_estremera

set the dpi to 300 and accept the Photoshop suggestion of using bicubic smoother.

 

- No. That's exactly what Scott was advising not to do.

 

Scott advises to let the print-shop do the upscaling, since it uses more sophisticated algorithms for scaling and sharpening that are specifically designed to work with the printer hardware.

 

You'd also have to create a ridiculously large 121 megapixel file to satisfy the 300ppi 'requirement' for a 30" x 45" print.

 

Leave the ppi figure alone to fall where it will when you crop. A 2000 x 3000 pixel crop will simulate a 24" x 36" print when actually printed to 12" x 18", and a 1600 x 2400 crop will simulate a 30" x 45" print.

If 'Resize' is left checked Photoshop will just rescale to whatever size you indicated at the default dpi (usually 300) and you will get a 30x45 at 300 dpi with massive amounts of fake information (interpolated) added. You do not want this. The lab should be doing this, especially if it's a Lambda / LightJet RA4 type printer, which is the most common type for online enlargements. They should also have no problem with a 30-45" file from a 24mb capture provided it's sharp and artifact free.

I disagree, because I think you have confused "resize" with "resample".

 

Resize is a major menu item in Photoshop. In the Resize dialogue box there are boxes where you enter the desired size in your choice of units, including "inches," and a box to enter the desired resolution, and a check box titled, "Resample." Once the numbers are entered, you should CHECK the Resample box.

 

In order to extract a smaller image for a test print, you should use the Rectangle Marquis Tool in the toolbox. At the top of the screen, you can set the dimensions of this box in inches (among other things), position the marquis on the print, and click and copy (ctl-C). That places the selection into Clipboard memory. Create a new file, which will open a dialogue at the same size as the clipboard, then paste in the new window. What you paste will be in a new layer, which you can keep or flatten as you wish.

 

Each time you paste a new clip in that window, it will go into a new layer, so you can slide and rearrange the clips (e.g., after increasing the Canvas Size). That way you can sample several areas of the large print, each one smaller than the maximum size of your test print.

 

You can also change the Canvas Size on the larger print and crop it accordingly, but you have fewer options how and where that crop occurs.

 

The Crop tool is not appropriate for this operation, since you can choose the shape but not the numerical size nor resolution.

 

Done in the manner I suggest, the sample print will have the same characteristics as a piece cut out of a print made at the intended final size.

 

An inkjet printer will ALWAYS resample or remap an image to fit it's basic format, such as 1440x1440 dpi. The print will ALWAYS have the same dot metrics, regardless of the size or resolution of the image being printed.

Edited October 25, 2018 by Ed_Ingold

Just got home and checked what steps I took and the results of each step.

First, I took my native RAW file and resized it using the image size window options. I resized one to 24X36, maintaining 300 ppi and the 'Resample' box was CHECKED. I did the same for the 30X45 size.

Then, I did in fact use the Marquee tool with rulers to make a crop of 12X18 inches on each of the larger image files. I didn't see that I could select the Marquee size, I just set the top left corner and moved the opposite corner until the Width and Height measurements were 12X18. Then I positioned the Marquee over the area I wanted to analyze on each print. I had to use the arrow keys to position it because I don't know yet how to just grab the selection and move it around. Then I selected 'Crop Image'. The resulting cropped sections, from each larger print, measured 12X18 at 300 ppi. I didn't select or specify the 300 ppi, it just came out that way.

So, after all is said and done, does it sound like when I print the 12X18 sections from each of the 24X36 and 30X45 images, that I will have the same degree of detail as if I printed the whole 24X36 and 30X45 print looking at the same area?

Whew. Sorry to put you all through this.

Just got home and checked what steps I took and the results of each step.

First, I took my native RAW file and resized it using the image size window options. I resized one to 24X36, maintaining 300 ppi and the 'Resample' box was CHECKED. I did the same for the 30X45 size.

Then, I did in fact use the Marquee tool with rulers to make a crop of 12X18 inches on each of the larger image files. I didn't see that I could select the Marquee size, I just set the top left corner and moved the opposite corner until the Width and Height measurements were 12X18. Then I positioned the Marquee over the area I wanted to analyze on each print. I had to use the arrow keys to position it because I don't know yet how to just grab the selection and move it around. Then I selected 'Crop Image'. The resulting cropped sections, from each larger print, measured 12X18 at 300 ppi. I didn't select or specify the 300 ppi, it just came out that way.

So, after all is said and done, does it sound like when I print the 12X18 sections from each of the 24X36 and 30X45 images, that I will have the same degree of detail as if I printed the whole 24X36 and 30X45 print looking at the same area?

Whew. Sorry to put you all through this.

 

You don't want the resample box checked when you upsize the print unless the lab has instructions to do this. I was going by memory but Ed is correct - it's the resample option (should be unchecked) after resize. By checking the resample box and increasing print dimensions Photoshop is now interpolating and adding information in a way that's rarely as good as the lab printer can. Commercial labs I get murals done at won't even accept upscaled files. They'll punt them back and tell me to let their printer do the upscale.

 

Again, most commercial labs are using RA-4 digital printers for volume enlargements, and the front end RIP on a Lambda or LightJet or Frontier will do a much better job than having photoshop rescale. Big reason these printers are so popular is they upscale anything to their native 300-400 dpi to huge dimensions and it holds up well.

 

Ink-jet is a different matter. They are primarly used at lower volume / fine art type shops and sometimes they require you to rescale to nothing less than 240dpi ahead of time. This should be on their main site for instructions. Funny enough but RA-4 and Inkjet based labs are kind of divided like the Hatfields and McCoys with each lab thinking the other guy's technology printer is junk. Unfortunately the net result is confusing consumers.

When resizing, you MUST check the "Resample" box. Otherwise the only dimensions changed are merely tags, not pixels. If the resized print is less than about 150 ppi, a high resolution printer will faithfully reproduces the pixel structure in all it's ugliness. An inkjet, for example, automatically mapping to 1440 dpi, will not add detail, nor smooth the data.

An inkjet, for example, automatically mapping to 1440 dpi, will not add detail, nor smooth the data.

 

- Yes it will, actually.

Here's an illustration to support the above:

First the entire frame of the example used from a 12Mp Canon 5D (original or mk1)

The car number plate at several hundred percent

And a macro of the printer output

Printer was a Canon Pro 5000, with no processing of the original camera image before printing to A3 size. QED.

I suspect the "cleaning agent" is the printing software or settings in the driver, not the firmware responsible for mapping images to the printer resolution. It could also be due to dispersion of the ink spray, causing the "dots" to overlap. Any idea what the ppi resolution of the image was at the print size above? The actual resolution of a printer is less than the spacing of the nozzles.

 

The process I described is determinative with regard to resolution sent to the printer, not subject to vagaries of the printing process. If the printer "improves" the results, okay, at least until you use a different printer. It's not hard to show pixelation in prints if the ppi is significantly less than the resolution of the printer. It's just as easy to avoid the problem altogether by printing at no less than 200 ppi in situation where the viewer can approach to reading distance (10" or so).

I suspect the "cleaning agent" is the printing software or settings in the driver, not the firmware responsible for mapping images to the printer resolution.

 

- Whatever. It's still impressively 'unblocky'.

 

I doubt that the most fanatical car nut could tell the make of vehicle from the collection of pixels, but it's easy to distinguish a Vauxhall badge in the print - with a strong loupe.

 

"Any idea what the ppi resolution of the image was at the print size above?"

 

- It's the resolution of a 5D (12.8Mp?) spread over an A3 print. Minus a bit of lengthwise cropping to accommodate the different aspect ratios. I seem to remember it was printed borderless.

 

An XT20 could provide just over 134 ppi on a 30" x 45" print. Which is easily doable IME.

Edited October 26, 2018 by rodeo_joe|1

When resizing, you MUST check the "Resample" box. Otherwise the only dimensions changed are merely tags, not pixels. If the resized print is less than about 150 ppi, a high resolution printer will faithfully reproduces the pixel structure in all it's ugliness. An inkjet, for example, automatically mapping to 1440 dpi, will not add detail, nor smooth the data.

 

This is entirely wrong, and I'm tired of arguing with you about it.

 

There is a big difference between a $80 desktop printer and a $75,000 LightJet or Lambda printer and front end software. In the later case the lab is investing in a commercial market segment and doesn't have time to play with DPI settings in photo files. When a professional client is having a 12 foot mural made and paying several grand for it they don't mickey mouse with DPI settings in photoshop . You really think that guy is going resize his file to 300dpi native in a mural that size?

 

A large format InkJet printer on the hand *does not* come with high end RIP software because of the drastic difference in price and market segment. Most small time inkjet / vinyl guys are going to making vector based advertisemenst that will rescale native anyways on the basic of vector conversion. It's typically a volume business. A guy running a 36" Epson in his basement likely won't invest five digits in software.

 

Do you even know what a RIP is? Do you even know what a LightJet is? Lambda? Inkjet printers which you keep talking about are the exception in the commercial photo printing world.

 

In the case of the RA-4 printers you want to present them with RAW data...not interpolated crap in Photoshop because the RIP on the front end of these beasts will do a far better job than Photoshop or any plug you have. The shop I have metal prints made paid $10,000 for their LightJet RIP alone which they also use for Metal Print dye sub printer. You can easily see the difference vs having Photshop interpolate and they won't accept upscaled files from clients.

 

Also, newer Lambdas are something like 400dpi. LightJets and Fuji Frontiers around 300'ish native. So, even if you upscaled the file to 300dpi in Photoshop that's not enough data for a lambda and the printer has to upscale to native resolution anyways. 300dpi is just an arbritary number that's deprecated in photoshop. It could be 287 or 323...doesn't matter.

 

You are also wrong with setting a lower end DPI limit. I go well below 200dpi all the time with metal and RA-4 digital prints and they look fantastic. With inkjet I don't because it's much higher mechanical resolution and the there's less diffusion not to mention the front end RIP is rarely there.

 

Rodeo_Joe is also correct on Printers doing it native, although the printer itself isn't doing it but the driver in front.

A 30x45" print is hardly "mural sized," and do not patronize me. I know what a RIP is, and for your information, they are perfectly at home with inkjet printers. The OP asked for a method to print a portion of large print as it would appear full size, a size well within the capacity of a large inkjet printer.

 

My dye-sub printer can easily resolve the pixels of an image sized for PNET. If you haven't looked, they look like little square bricks, especially in diagonal edge detail. I daresay most images submitted for commercial printing have been rendered using "crappy" photoshop, even "crappy" Lightroom.

 

At least you admit that inkjets have higher resolution (typically 720 dpi). My "crappy" dye-sub is 600 dpi, and each dot is blended 3 colors. For best results on an inkjet, you should consider sampling to a integral subset of 720, such as 360 or 180 ppi. While that may present fewer opportunities for the printer to mess up, in my experience, it really doesn't matter as long as the results are at higher resolution than seen by the. unaided human eye.

 

For commercial printing, I ask the service bureau what they want for images, and comply with their requests. If they want images without resampling, and RGB v CMYK, that's what I send. But I review samples first, or refer them to the art director.

Edited October 26, 2018 by Ed_Ingold

Hey guys,

 

This has been unusually informative. I completely agree and have experience to back up that if I was going to use a high-end printer for the larger prints, I know to just hand over a high-res TIF of whatever my camera yields and let them handle it. Back in 2012, I produced a variety of black and white images of New York City architectural details that were used extensively in a marketing campaign for a real estate company. The cameras I used were a 12mp XSi and an 18mp 60D. I nearly fell over to see how great the prints looked when printed with dimensions measuring in FEET, not inches. When I spoke to the printer, my first question was what method did he use to uprez the images. He said he did not uprez. Just printed at the size the client wanted. I will assume that he had the front end RIP software that managed the quality of the output. But in this case, I'm just using the online Adorama print department to get an idea of how the details of larger prints will look. I also did crunch the numbers and see, as Rodeo Joe said, that natively, the Fuji would yield around 133 dpi at 30X45 which should be 'doable'. Rodeo even inspired me to change my username to Cowboy Bob.

 

Thanks all,

You guys have been great.

Cowboy Bob

Rodeo even inspired me to change my username to Cowboy Bob.

 

- Hey! I was thinking of registering that as a trade name.

 

Long story how I chose that name for my avatar, but I won't bore you with it now. :rolleyes:

 

Good luck with the big prints. I'm sure they'll be fine.

Here's an illustration to support the above:

First the entire frame of the example used from a 12Mp Canon 5D (original or mk1)

Printer was a Canon Pro 5000, with no processing of the original camera image before printing to A3 size. QED.

The example proves nothing too useful other than what you see on the screen and what you see on the print appear differently.

Depending on the print driver, there's no resampling whatsoever. The OS may again depending on the driver. In the case of both Epson and Canon, the native drivers do not resample the data but again, the OS may and how and to what quality is highly questionable.

Finding the Right Print Resolution - Digital Photo Pro

The people at Epson say that the print driver doesn’t do the re-sampling, and since the application sending the print doesn’t do the resampling unless asked to do so, the resampling must be happening in the print pipeline. I’ve tried, unsuccessfully, to get confirmation from Apple and Microsoft about their respective print engine activities regarding the resampling of the image data. So I really don’t know where or how the resampling is being done. But I’m convinced some sort of resampling is being done. Is it an optimal resampling algorithm, or is it something done for speed? I don’t know, but I suspect, at best, it’s a compromise in favor of speed. I’m pretty sure there are better, optimized resampling algorithms that could do a superior job. In fact, Adobe Photoshop Lightroom resampling is a hybrid Bicubic algorithm that interpolates between Bicubic and Bicubic Smoother for upsampling and Bicubic and Bicubic Sharper for downsampling.

 

For the OP: you don't want to resample of course. But you do want the resolution tag in the document to be set to what the lab recommends or you intent to send for the final as it could be read and it's possible, based on lots of factors we may never know, that resampling could take place. In the front end processing or the driver or printer hardware.