There should be some instructions in the package if I remember right. I made some a couple of years ago, and I think I probably printed at around 300ppi, although I don’t remember now. And don’t forget to change the JPEG to a non-lossy format before you work with it. 180ppi is just barely enough resolution as it is, you don’t want to risk losing any more quality.
Consider that the fabric (and the transfer paper) you are transferring the image to cannot support ‘photo-quality’ settings. I’ve done T-shirt transfers at 150PPI with fine results. The trick is to adjust your printer settings, not the image resolution. Perform a test at ‘med’ quality and ‘photo quality’ printer settings, which is really varying the amount of available ink for the fabric.
Best regards
Walt
Beth and Walt, thanks for the help. The photo I was sent was large enough that I could shrink it to 300 ppi without resampling. I have an Epson C82. I chose "photo" as opposed to text, text and images, …, and selected the paper setting "photo quality inkjet paper". I printed it on Office Depot iron-on transfer paper. I took it to a local T-shirt shop. They included pressing on the transfer in the price of the T-shirt. Turned out great! I had wanted to print it on a dark color T-shirt but was told that the home-made transfer (as opposed to "commercial") must be used on a light color T-shirt, preferably white, or the color will show through. They also told me the T-shirt should wash well.
Eva