(c# Photoshop sdk) How can I prevent Photoshop from turning on?

[Sup.SH]

I use the below code, 

      string pdf_fileName = "C:/.../.pdf";

      Photoshop.Application pdf_photoshop = new Photoshop.Application();

      pdf_photoshop.Open(pdf_fileName);
              ...

      pdf_photoshop.ActiveDocument.SaveAs(".../.tif", option_save);

      pdf_photoshop.ActiveDocument.Close();

      pdf_photoshop.Quit();

And Photoshop appears on the screen and then turns off. (Like below picture)

I wanna Photoshop to work without turning on. Is this possible?

[Lumigraphics · Accepted solution]

Photoshop has to be running to perform any operations. You can look into Photoshop as a Service to see if that might be an answer.

https://community.adobe.com/t5/photoshop/photoshop-as-a-service-api/m-p/10557988?page=1