I use the Canon imagePROGRAF PRO-2100, which is Canon’s line of Professional Photo Printers. My printer is a 24” width and use only Original Canon ProGrapf ink and Canon Premium Matte 230gsm paper.
I normally print posters at 18x24 however I can print up to 24x36 and panoramas with 24” widths. I can also print smaller prints but we will have to print where we utilize as much as the 24” width as possible. So if you wanted a 11x17, we can put two 11x17 next to each other to maximize paper usage.
For a 18x24 inch poster, you would need a high resolution camera such as a Sony a7R III with 42mp to utilize native resolution. However due to the fine printing ability of the Pro2100, even stretch pixels show really well. I have seen 20mp go to 24x36" no problem.
If you are using Photoshop, please make a blank canvas at the W x L of your desired size at 300dpi, 8bit and sRGB profile. When you drag the image into the canvas, make sure that it is a smart object before resizing to make sure the quality stays on point.
One of the ways to combat lower resolution for larger prints is to add a large white border matte. Not only does this keep the resolution more true to its native resolution, but the matte border does add a bit of fine art feels to the photo. In addition, adding the border allows you to keep your original composition of 2:3 and not have to crop into it if you are doing a 18x24, which is a 3:4 ratio. Please be aware of that.
I can also prep and edit your image for an additional $7/image. That will include adjustment to exposure, color toning and file prep only. No photoshopping.
Both of my monitors are calibrated using X-Brite i1 Pro Display. I use a Mac Pro tower with dual 30” Apple Cinema Monitors
I have been a photographer since 2001 and I take resolution, pixel peeping, native size printing to the highest level. I will always make sure to help you along your journey of printing your memories for the wall. If you have any questions, you can always email me at firstname.lastname@example.org