[jatrax]

Oh, I completely agree. He's not likely going to get printed images for close viewing I would personally pronounce suitable for sale to a discriminating buyer today from a 4-5 year old inkjet printer.

I'm not too worried about the age itself, my primary concern is that the printer was not designed for artwork. Maybe it is fine, maybe not. And the OP called it a plotter but it is in fact an inkjet so maybe it is OK. But he has a shot at a showing, I would just buy the prints and have done without taking the chance in this case. Unless he has the chance to do testing or more research on the inkset.

Back a few years I was offered the opportunity to show some framed prints at a local gift shop, not really a 'gallery' but for me it was a start. I was using a Canon i9900 at the time and thought it would be fine. About a month after the hanging I got a call to please take my prints down as they had faded. And they had, quite badly. The shop was quite bright with windows, and I did not know any better and neither did the shop owner. But it left me very gun shy about producing work that stands up in the shop and after the sale. Now I test and make sure anything I send out to a customer is something I am proud of.

[MrNPhoto]

I have access to a HP DesignJet 4500ps at work. Boss said I can print for free, no worries.
We have a very nice matte photo paper as well I can print on.

I read the specs online and it says it's best used for technical applications and production work (we use it for geospatial applications)

Would this suffice for my photography?
Most will likely be A2 or A3 sizing...

Another thing I'm confused about:
Is there a preferred workflow for printing?

DNG to LR > Edit > Export to Jpeg/Tiff/PNG? > Print?

Any help would be appreciated.

Here is an example photo I would like to print (A3)

I have experience with HP DesignJet 5500ps (A six color plotter - yes, it's an inkjet printer, but everybody at work calls the large format printers 'plotters'). They were designed for roll-paper only, in large volumes, at poster sizes (A1 and bigger). For large poster-sized prints, they produce acceptable quality, since you tend to look at the prints from a greater distance. Mine is dye-ink only, and can have some significant color fading issues on certain paper types (non-photo matte papers, especially). My prints are for temporary use, so image permanence is not a concern.

When using photo satin/luster papers, the printer can put down lots of ink. Mine has a heater plate under the paper output, and I set it to Max. when printing on photo paper. Don't let the printed front surface of the paper come into contact with itself until it is absolutely dry - it will fuse together, ruining the print.

Do all your color/contrast adjustments in PS or LR - try to avoid any of the adjustments available in the printer driver. This can cause major slowdowns in the speed of the print. I often export as JPG or PDF depending on what I need, and notice no quality difference compared to TIFF (which is much, much larger file size).

I recommend you experiment with the printer, to get a feel for what large format printing is like, and how printing large affects your image's 'look'.

Summary: Good for large poster-sized prints, with acceptable quality. For exhibition/sale of prints, where quality and longevity matters most, I would use the pigment Epson K3+ printers instead. For smaller paper sizes (A2 or smaller), desktop printers offer much more flexibility in paper sizes, paper types, and paper handling options.