I am an outlier in the world of fountain pen users in that I use a database to algorithmically select which pen, nib, and ink combination should next enter rotation.
Why? Well, my day job is very much IT focussed and I get to "play" with databases a fair amount of the time so it was not unusual that in 2010 when I came to dealing with my burgeoning fountain pen collection I turned to a technological solution to manage it. To balance my strictly PC/Microsoft work world I am a 100% Apple product user in my personal life, so the solution I chose revolved around an Apple product - Filemaker Pro. Unfortunately this is a business-grade database solution and with that comes with a business grade price (I just updated to version 14 for the princely sum of AUD$250). In hindsight I could have achieved a similar result by using a spreadsheet application especially to record data around my purchases but I think I would struggle to get the same benefit on algorithmic selection of the next into rotation. My current collection of 90 pens, 116 nibs, and 279 inks give rise to a very large number of possible combinations.
The image below is my In-use page from my database. Yep only three pens in rotation at a time.
The same three on the one per page version just for added bling...
So how does it all work?
Well each of my pens, nibs, and inks are assigned an UID (unique identifer) for me it is a 3 digit number starting at 100 i.e my first item is 101 etc.
One of my writing samples images below showing the UIDs 156, 166, and 381. The other three values are the date in DD/MM/YYYY style (Sorry, but not really sorry, US readers) :)
I have master tables for each of the pens, nibs and inks where I record data about them. Data recorded for pens include all the normal purchase fields like when bought, from whom, price paid. I also record particulars about the pen such as what nib came with it, new or used and an image of each pen. I also give each a rating in the range of 1-5 (where 1 are my precious, expensive pens and 5 are ones that are for any use) to allow me ban it from being used with certain inks (the reason for this will come apparent later).
A fragment of my pen master table.
The nib table is similar with purchasing data and image, though data about the nib itself is expanded to include whether it is factory or a custom grind and rating is given out of ten to include my feelings about the writing quality of the nib.
A fragment of my nib master table
Lastly inks get pretty much the same general fields as pens and nibs but have some other fields relating to colour such as scan of each ink's swab and image of the bottle with label and most importantly they also get a rating 1-5 of how dangerous this ink maybe to my pens. Why? - Well I own inks that have been known to stain - Noodler's Bay State Blue tops this list so it gets a rating of 5, 1s are normally only given to inks from manufacturers that also make expensive pens (my theory is that they are unlikely to sell an ink that will cause damage to their pens), so 2s are allocated to safe inks from non-pen manufacturers, 3s and 4s are given to ones with super saturated colours or special formulation from non-pen manufactures - lots of my Noodler's ink fall into this category.
A fragment of my ink master table.
So for a pen to be used with an ink the pen rating has to be equally or higher than the ink rating or if you look at it from the ink side an ink has to have a rating equal to or less than the pen. Those inks that fail this test will never be used with that pen.
This is going to get way more nerdy but stick with it. :)
So I have my master tables for each of the pen, nib and ink. I also have a table that records the history of each combination. The includes fields holding date into use, date out of use, status, duration, comments on the combination etc. Currently this table holds 864 records dating back to October 2010.
To allow me to use an algorithm to propose future combos I created a few other reference tables. One holds pens and nibs which lists all 1,136 valid combinations of my pens and nibs , another is pens and inks which lists all 25,389 valid combinations of pen and ink, and lastly a tables that holds the 32,643 valid combinations for nibs and inks. These tables extract data from my main history table to show if a combination has been used, if so, how many times, and how long ago.
I have three other reference tables to how the current status of my pens, nibs and inks. These tables also act one of the building blocks to get to the next combinations.
The major factor determining items for the next combination into use is the DSLU (days since last used) value of each of the pens, nibs and inks. Originally I used DSLU as the sole factor but that became a bit boring as my pens would return to use in pretty much the same order.
So begain a lot of tinkering with other factors to give some variation to the DSLU order, I won't go into the long and much more boring history of what I tried. I wil simply (LOL) explain what I do now to gamify my rotation.
I try to apply a weighing factor so I don't get too much of any one ink colour or items for the same manufacturer of pen or ink into use at the same time.
Current I do this by looking at the last 17 combinations into rotation and applying a ranking where the oldest is a 1 and the three in use at all given 17, with those in-between ranked along the way.
I sum these scores and writing the totals to three other reference tables (Colours, Ink Man, Pen Man). I then subtract these score from the maximum of those scores so that I get a range of positive values (SC column).
I then link these scores (SC) back to the respective current status tables, using Pen Man for the pens and the other two for the inks. Within these tables I apply a range of other 'fudge factors' just for futher variation. These include adding the number years owned and also a number out of 12 that respresents how close the item is to its anniversary of entering my collection.
I am constantly trying to strike a balance between those pens and inks that have been in my collection a long time and those that are new. Lately I have noticed that my Pelikan pens were being overly penalised because they make up the single largest portion of my pen collection so I have added a factor to the pen calculation to give a bonus if DLSU is greater than 250 days. At the moment most Pelikan's return to use on average after 262 days compared to 191 days for other makes. Inks however are taking more than 600 days to return to use, and this extends by 30 days with each new ink I purchase.
Calculations happen and the proposal for the next pen, nib and ink combination page is displayed below. Actually it is three pages as I currently select only one pen, but allow display of the top three nib choices each with the top four ink choices.
So the next pen is my Lamy Studio Violet Limited Edition with top nib choice of a stainless steel oblique medium nib, with Noodler's Dostoyevsky as the top ink. Interesting enough Dostoyevsky, an ink that has had one previous use has pushed ahead of the Organics Studio ink that has yet to have its first use. The reason for this is most likely found in the ink manufactures table where Organics Studio has a score (SC) of 22 and Noodler's of 49. The 27 difference is enough to overcome the bonus a never used ink gets in the calculations.
So that's it in a nutshell :)
Thank you if you have made it to here. You probably think I am mad and you aren't the first...
If you think that it all seems way too controlled and lacks free-will, you again will not be the first. I sometimes agree, so now and again I disregard my database suggestion and ink up a combination of pen, nib and ink that I really, really want to try.