I had the opportunity to do some research in the Diocesan Archives of Tarnów when I was in Poland.
The process is simple... you must sign in the "guest book" and then if you have not been to the archives before, you will need to purchase a researchers id card which is good for that calendar year. Of course you must present some identification which for the foreigner would be your passport.
If I recall correctly it cost about 15 złoty which is roughly about $5 give or take depending on the exchange rate. Research time costs 6 złoty per hour.
The Archive is open Monday thru Friday 9 am to 3pm with a break for lunch from noon to 1pm. On Saturdays it is open for only 3 hours from 9am to noon.
This is tedious work. There are no "books" per se, but instead bundles of old paper. Each bundle contains a span of years worth of records for either birth / baptism,
marriage, death / burial for all villages of the parish for those years. In addition to the standard metrical records there are other various misc. types of records available, including parish correspondence.
Each priest would make hand copies of the church books that would go to the Diocese. Each bundle of records contains those pages put into alphabetical order by village name.
Since you are handling individual sheets of paper, extra care must be taken not to damage the old documents as you move them to a pile of finished pages. Some of the pages show their age with areas that may be missing because moisture and molds have done their damage years ago. In some cases, areas of the page were left unreadable because that section of the page was already gone. It is always advisable to wash your hands after handling those documents.
I was thankful that there were not that many people were there researching at the same time, as there were times when many maps were dragged out, reference books and documents all at the same time. A majority of the table space was available to spread out.
A number of reference tools were also available. A special map of Poland detailing all the parishes within the diocese made it a lot easier when trying to figure out what parish records needed to be searched next. The other item that was useful to me was a book that shows the parishes and all the villages that a particular parish serves. It also lists the villages that it served at one time, but no longer serves, but does say what parish serves that village. This type of information is not available online. You would have to get that information from this book. If I understood correctly, this book is republished about every 5 years with updated information.
After research at the archives was complete, I asked and received permission to photograph their library, so I could share it with everyone. This will give you a little bit of insight into what the Diocesan Archives of Tarnów looks like.
I can not say enough for the staff that work there, they were very friendly and helpful. The priest in charge there became quite interested in my project, as I was not finding records that should really be there. When all was said and done, it was concluded by everyone who had been listening and keeping up with the frustrated search that it appeared that the priest had not kept consistent records. It did explain a lot when I was not finding what I knew should be there.