Phil Hamling

376 County Route 1

Warwick, NY, USA 10990


Friends' Work

Forum For Five

Zinc Silicate Crystalline Glaze Pottery

A chronicle of my recent progress and a way for me to keep it straight in my head!

Click on thumbnails to enlarge photos

Info I've been asked to keep in confidence.

Crystalline Glaze Information


Temperature Conversion

Crystalline Glaze Variables

Bailey Pottery

US Pigment Corp.

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September 27, 2007 33rd Firing Results

Same firing, same glazes (except for the glossy white liner) with the same kind of results. Nice!

It is strange that ^11 did not go down as far as in the previous firing. I would have expected it to go down more due to element aging. I wonder if it's due to the room temperature being 95F this time compared to 72F the last time, or if it is a slightly smaller load.

I'll have to cut these catchers off with the diamond saw.

The liner did not devitrify after 6+ hours of crystal growth holds.

These came apart easily with a torch. I think I'm seeing that if you open the kiln below 200C (say 150C) there is enough thermal shock to make the catchers fall off themselves. If I cool to ~50C I need to torch them, but only ever so slightly.

September 25, 2007 33rd Firing Setup


New elements? Nah! Change the hold time? Nah! Change the glaze? Nah! Well I did put a glossy white liner in a few of the pieces. Other than that I'm trying exactly the same thing I did in the last firing with the same glaze that was on the bowls. I'm curious to see if I can get the same effects and if  the elements age more and cone 11 goes down further.

September 20, 2007

September 15, 2007 Photos from Krystallos 2007

Being at Krystallos 2007 was like a dream come true for me. I can't thank all of you enough for the warm camaraderie I felt. Although I never met anyone before this event, at the first night's dinner I felt like I could go up to half of you and say hello on a first name basis. It was great. The next 2 days events were amazing too (not to mention Jamie Kozlowski's shadow puppets.) I really didn't have much time to take many pictures though. I didn't want to miss anything. I did get some, but William and John and the rest of you, I can't believe I didn't get your picture!

Photos from Krystallos 2007 at Bill Campbell's

September 11, 2007 32nd Firing Results

Never Forget!

I changed the firing cycle to go directly into a 3 hour soak at 1080C followed by 5 successive 10 minute long ramps to 1000C with a ten minute hold then a 10 minute ramp back up to 1080C with a 10 minute hold. Some of these pieces have a real psycho look where the 5 rings run between small crystals that started part way through the first hold.

This time I added a cone 11 to the mix to see just how much past cone 10 my aging elements were going. It looks like I got all of cone 11. It seemed to help the over nucleation situation but the crystals are not as large as they've been in the past. The puzzler is how far do I go. Should I run them to failure? Run the risk of way over firing and ruining a load?

The pot pictured in the lower left corner above (light brown background with silver blue crystals) is made of Fallon Classic clay. It had zincite seeds pressed into the leather hard body. It seemed to work OK, but I was surprised how much they ran. I tried to pick small pieces.

September 10, 2007


Diamond hand lap used to remove zincite seed protruding from the surface of the piece. With just a few strokes and light hand pressure they are quickly smoothed down.


September 9, 2007 32nd Firing Setup

Besides being one of the denser loads in a long time (one shelf of test tiles on the bottom and 8 pieces on top) this firing has 5 different glazes. These include 8% titania base with :

1) 5% CuCo3  over fish scaled bottles from the previous firing to try and cut the scales.

2) 4% CuCo3 on a fresh bisqued bottle.

3) 2% Nd2O3 to try and get silver crystals on a purple background after reduction at Krystallos 2007 (hopefully.)

4) 1% CuCo3 +.3% Fe2O3, and

5) 2% CoCo3 +.5% MnO2


I've noticed cone 10 falling further and further as my elements age. My kiln is programmed with a rate of rise to a temperature with a hold to get cone 10 touching. I surmise that as the elements have aged they are not able to keep up with the rate producing more heat work by the time top temperature is reached. The last firing is in the front.



September 8, 2007 31st Firing Results

These pieces are made using 2 clays, Tucker's 10-85 Translucent Porcelain and H.H.P. Porcelain. There seems to be little difference between these 2 clays. Both show very little back ground with the uncolored glaze. The pieces with the most copper carbonate have the most background and those with an intermediate level have an intermediate amount of background. There is a large difference between the nucleation rate from these 2 clays and that from the 2 grolleg based porcelains I've used (Standard Clay Co. Grolleg Porcelain and Miller 550 by Laguna Clay Co.) I have some pieces made of these 2 plus Fallon Classic almost ready to glaze.

I plan to add more glaze containing a higher level of copper carbonate to some of them and refire tonight. There should be some interesting raku effects in the copper pieces.

The revised firing schedule had an effect in that I can see a repeat of three ring sequences at the low end, but it is too subtle. I plan to raise these lower holds and slow the transition between soaks.

September 6, 2007 31st Firing Setup

This is the last batch of bottles Chris Groat threw before heading off to medical school. They are glazed with 8% rutile base, 8% titania base with 2% copper carbonate and a mixture of the two. It will be nice to get a few pieces for raku at Krystallos 2007 next weekend.

I am using the 16 segment program as defined below except the lower 3X repeating sequence of hold temperatures have been raised from 954C & 925C to 1000C & 975C. I hope my elements have enough life life left in them to go through the cycle OK. I haven't seen any change in performance as evidenced by cones yet, but the elements themselves are starting to look beat up.

September 3, 2007

I haven't fired anything in over 2 weeks! It's making me buggy. I finally got Chris' bottles wet sanded and ready to glue to glaze catchers. I'm trying to get some pieces glazed and ready for Jesse Hull's Raku at Krystallos 2007 in addition to just getting something going. The last of the latest glaze catchers and a few new pieces are in bisque fire tonight.

My new initials stamp turned out OK. I machined 2 of them (0.65" dia. & 0.75" dia.) on one of the CNC routers at ZIRCAR. It gives detail I couldn't get with my hand carved one.

Clear acrylic allows you to see through it as the impression is being formed in clay.

The machined image is reversed from the finished one.

The first piece I made was a positive image. Only after looking through it I realized I had to reverse it to get it to work right.

August 26, 2007

A bowl by Chris Groat  with 3% CuCO3 in 8% titania base before (above) and after (below) post fire reduction by Terry Fallon.



 I wore a chunk off my right middle fingernail throwing all this stuff. I need an alternate technique.

 August 25, 2007 I threw about 25 glaze catchers in a little over an hour using my new favorite tool (see below). I should be a glazing fool pretty soon.

It was 93 degrees. This group I threw about a week ago dried that last bit pretty quick.

I think she's losing it! Kat found out how to use the self timer feature on my camera and came up with a few neat shots. I think the joy of making the Warwick High School Junior Varsity Cheerleading Squad has sent her over the edge.

August 20, 2007  2 Lids.

Where did that angle come from 1/4 of the way up the pot?

Adelaide Alsop Robineau

August 18, 2007 A little help from John Tilton (Dialogue)

I tried and think it helped, except I missed the part about the widest point of the pot being about 2 inches below where it is now.

August 16, 2007 L&L Kin uniformity tests, ^05, Fast Bisque

August 15, 2007


August 13, 2007 30th Firing Results

August 12, 2007 30th Firing Setup

Next Day Observations

I saw it flip over into User 6. When User 5 was complete the controller seemed to hesitate and then displayed "On". I saw the temperature rise to 1025C, hold for 10 minutes then drop to 950C. It took 18 minutes , a rate of ~335C / hr.

I finally go to glazing the lidded pieces that seem like they've been around for ever. Two pieces have 2% copper carbonate in the 8% titania base. The other is a 50 - 50 mix of this and the 8% rutile base. Chris Groat's chalice is all rutile base. I seeded all the pieces and increased the soak at top temperature to 15 minutes.

Quite an array of "stuff", making for a tight load. This is the debut of my use of the Fallon Stilt method. It's only ~1/2 as densely packed as the kilns I saw Fa load.


Sometimes I don't think I'm smarter than a 5th grader. After reviewing the rings form the last firing I see I didn't get 16 segments - only 8 (even though I said I did.) I'm hoping it's because the soak temperature of first segment of "User 6" (975C) was set to less than the ending temperature of "User 5" (1000C) as you cautioned. I changed it to go up to 1025C. Keep your fingers crossed.


I didn't get the 16 segments as I originally thought  - only 8.


"Bella" joined the family this weekend.

August 8, 2007 Before and After, Thanks to Terry and the JMH-5F Reductionator


Light Reduction   Less Light Reduction

Two pieces from the 28th firing which Terry put through the new electric post fire reduction paces. Both have the same glazes. 8% rutile base with 2% CuCO3  on the outside and 8% rutile base on the inside.

August 7, 2007 29th Firing Results

I think I had 2 very nice pieces come from this firing including the first of Chris Groat's bowls (with a pinhole in the bottom) and a piece with Fa's Celestite (sp?) with nickel glaze from the workshop over red stain. The hole let a lot of glaze through the bottom of the bowl and seemed to leave just the right amount for Wild Williamesque needles to grow and the higher firing thinned the crystal herd allowing more of the red stain to peek through.


The 3 cones came out within a fraction of each other. Notice on the top one I scr*w*d up an put ^9 behind ^10.

The workshop dog with 5% barium improved after refire with a layer of titania base w/ 4% MnO2. The one with 5% erbium did not.

The next time I fire nickel over red stain I will soak longer to show more background. Maybe an additional 20 minutes will do it.

The 16 seg. firing did happen. I got more low end rings, but they don't repeat 3X. I guess the holds were too low and growth stopped so the cycle didn't start back up.

New L&L Kilns being installed at work.

An interesting Article....Fluorescent Glazes

August 5, 2007 29th Firing Setup

     Re-firing 2 pieces from the workshop that had no crystals*, a piece with nickel over red stain (like the one below except I'm hoping for more background as Fa only fired at a rate of 9999 to 2300F / 1260C - I never saw cones) plus one of Chris Groat's bowls with 3% CuCO3. I'm trying to use the 16 segment cycle again (for the first time successfully - see July 28.) to get the white, black and brown rings at the low end with copper.

*All right! One puny little crystal.

August 3 - 5, 2007 "Mastering Crystalline Glazes" Workshop with Fara Shimbo at Wesleyan Potters

What a great facility and wonderful people! Its like a pottery country club. I would recommend a workshop here to anyone.

July 29, 2007 My New Favorite Tool

I came up with this tool to help make glaze catchers exactly the size I want with well formed top and side surfaces. It turned out to be simple to adjust and use.

A combo of 304 and 8-18 Stainless Steel.

Set the length to exactly the right size.

Form the catcher to the rough size.

Shape the top and sides while matching the diameter.

July 29, 2007 28th Firing Results

I must have blown it because the firing did not link to the second program to give 16 segments. It simply shut off and crash cooled. I'll have to be more careful next time and make it happen when I can be near by during the transition. No psycho rings this time! Hopefully next time!

More results from the Fallonator

Before After

The largest piece is  8” tall with a 3” crystal.

July 28, 2007 28th Firing Setup

Included are 2 pieces with 3% CuCO3 for the Fallonator, 1 lidded piece with 4% MnO2 And Kat's Whachamacallit.

I finally took the time to read the controller manual to figure out how to link to programs and get 16 segments. This firing includes a series of low ramps and holds in an attempt to get some Mankameyer / Fallonesque Psycho Rings!


July 22, 2007 27th Firing Results

July 21, 2007 27th Firing Setup

Three more pieces made of FallonClassic clay. Two with 2% Nd2O3 in the 8% titania base and the last with 8% rutile base. They should light up purple and gold in the Fallonator.


26th Firing Results

July 20th 550C Sneak Preview.

 I know I'm a bad, bad, bad, bad boy, but I couldn't resist. I got paid back with a really lousy photo. I guess I was too afraid to hold it open long enough to let my camera focus.

July 19, 2007 26th Firing Setup

Chris' goblet is glazed with 4% MnO2 colored (non-crystalline) liner glaze on the stem, with 2% MnO2 + 1/2% CoCO3 colored titania base on the top. I have it placed, without a catcher, on a piece of alumina fiber insulation (just in case.)

Added 2% Custer Feldspar + CMC Paste to 1% NiO colored clear base trying to flux over-nucleated glaze

This firing includes 2 of Terry's pieces (2% MnO2 + 1/2% CoCO3 with clear titania base 1/2 top coat, a goblet by Chris Groat, a nickel glaze refire and one of my pieces.

Insulation extension waiting patiently for the next time.

July 17, 2007 25th Firing Results

The fibrous insulation I used for the temporary lid is just too good an insulator. The kiln was way too hot to unload, or even get a sneak preview shot last night. It was still pretty warm this morning. I'll have to learn to be patient, or when to crack the lid.

July 15, 2007 25th Firing Setup

Today I finally got a firing loaded. And a heavy one at that. I finally got to glaze the 2 tall vases, Chris Groat sent a long time ago (with rutile base) and a lidded piece I made in 1979. I hope they come out OK and there is enough time for him to do the Reductionator thing before heading off to medical school. The results should be interesting.

My last firing was 29 days ago. It's felt like withdrawal. In addition to the non-crystalline glaze activities spotlighted below we had my son's high school graduation party last night. Fortunately everyone and most things came through intact. 

The weather was perfect. 70's, sun then stars, low humidity, no wind at night - or bugs! The house was packed. Hundreds of people - a lifetime of friends. Cars lined both sides of all 700' of the driveway.

Electric Reduction Kiln Update

I had a chance to speak with Gary Schwartz, I Squared R Element Co. last week. He said the spiral groove element does not seem like a good candidate for an electric reduction kiln. The concern is with carbon condensing on the elements and in the walls of the furnace causing a short circuit and catastrophic failure. He offered an alternate element type and layout where this will be less of a concern.

July 11, 2007 Post fire "light"  reduction by TerryFallon. "Before: (fired in oxydation) on the left and "After" (fired in light reduction) on the right.

July 8, 2007

  Test tiles of FallonClassic Chris' Bowls

Electric Reduction Kiln?

I built this unit in ~1982, It uses 8 Spiral Groove SiC elements (I2R Type SER), platinum t.c., low density alumina fiber insulation, runs on a 120V, 20 amp circuit and has been operating as high as 1500C (2732F) I think this system will be useful in an electric reduction kiln as the manufacturer's literature says they are rated to 2500F in hydrogen). This unit is a little on the small side, as it was built as an R&D test kiln. A bigger unit would be no problem.


A New Army of Test Soldiers

July 5, 2007 July 6, 2007

I applied 20% inclusion stain containing engobe to 17 pieces to help get a better handle on what it takes to make them all give nice crystals (hopefully).



More Fish Scales

July 4, 2007

Golf Green Repair

July 6, 2007

Our front yard made the local paper



Better Picture

PS: I know this is off topic but it is what's keeping me from more crystalline glaze work.


I made a temporary lid and height extension to allow me to fire Chris' tall vases and another piece I have. That CNC Router comes in handy again!

The bands from the 1000C hold contrast well against the darker 1080C hold on the Mn - Co glazed piece.

The crystals have almost a surreal look to them

I probably won't put any new photos up for ~ 2 weeks. I am going to the Thousand Islands fishing this weekend and am not sure about next weekend.

I have been amazed at how many visits this page has gotten. My estimate is 40 per day. I guess other people are as intoxicated by crystalline glazes as I am. Now it is 10:18pm NY time and the hit counter says  5090.


6-18-07 24th Firing Results


6-17-07 24th Firing Sneak Preview (Avril, It was at 220C, I couldn't resist and tried to move quickly!)

The 1% NiO glaze on top of the refired pieces really seemed to make a big difference.  I hope the small vases hold together this time. I'll know tomorrow after it has finished cooling slowly.

The nickel over inclusion stained piece is a dog again. But notice the small test tiles below it have the "Orange under Blue" look to them. I'll have to dig into exactly which stain, at what loading, actually works.

"David" seems to have some pretty interesting halos from the 1000C and 900C soaks.


 More reduction magic by Chris Groat. He reduced the bowls from the 20th firing.



6-16-07 24th Firing Setup

This time I made sure the 1% NiO glaze had rutile and not titania and used it on another red inclusion stain piece.  I also recoated the last major nickel dud plus the cracked pot that didn't make it from 6-14-07 and it's brother. Maybe the glaze will fuse the pieces together.

"David" is in this firing wearing a 2% MnO2, 1/2% CoCO3 glaze as well as the second of Chris' large plates for refiring.


23rd Firing Results

After the third firing, and a total of 50 minutes soak at top end there are fewer crystals on the plate and they look "smoother". Some of the inclusion stain is beginning to peak through the ni - ti glaze, but it's still a dog .

Before this re-fire cone 10 (on right of picture) from the previous firing was touching. After this firing it looks like much more heat work took place.



6-15-07 22nd Firing Results (450C Sneak Preview) and  23rd Firing

The refired pieces show some improvement. The close up comparison on the right shows some of the detail. The nickel piece has larger fish scales and more crystals on the inside. More glaze has flowed into the catcher too. The plate has some background showing on the rim now.

I decided to fire these again for a third time without any additional glaze and increased the top end hold from 10 to 30 minutes.


 6-14-07 22nd Firing

Left: Refire

Right: It didn't make it.

Avril Farley wrote: "I'd like to see the result you try refiring one plate and the over seeded inclusion nickel  with no additional glaze and nothing else in the kiln. " Here goes!


6-14-07 21st Firing Results

Let me deal with the good first!!!!! The 1% NiO in 1% titania glaze looks good on the small bowl made of "Unknown" clay. The (few) crystals on the Laguna 550 clay have an interesting shape and orientation (no seeding). Other than that I have to say the results of this firing are disappointing. I think I did jinx myself by crowing about how the 8% rutile base is fool proof. It fish scaled!

The inclusion stained piece is a total bust. It must be the rutile that made the previous piece tick!!!!

21st Firing

I think I made a big boo boo! As I was walking away after pressing the start button I realized I had mixed the nickel oxide glaze using 1% titania rather than 1% rutile. I had my fingers crossed that it wouldn't make a difference. I think I see it makes a big difference on the inclusion stained piece. Rather than looking like the piece from my 18th firing, this piece has the over nucleated microcrystalline look I've seen on test tiles before.

6-12-07 6-13-07
Setup 700C Sneak Preview

Chris' large plates on bottom shelves with 8% rutile base on top, white liner on bottom. The pieces on the top shelf are all glazed with 1% Green NiO in 1% titania base.

Nickel on 4 different clays. 11:00 and 4:00: Laguna 550, 1:00 Inclusion Stained Tucker's HHP, 6:00 Highwater P-10 & 9:00 Unknown

6-12-07 20th Firing Results

6-11-07 Preview "Let's Make a Deal" Bowls

Fish scales on top.

A little bit of background showing on the rim.

Nice crystals on the outside.

 Yellowish P-10 porcelain  tall vases and plate*.


*Chris, It looks like P-10 has something leaching out while drying. Notice the yellowish color? I wonder if that has something to do with it making fish scales. I wonder what the vases will do with nickel?


6-10-07 20th Firing Setup

2% Nd2O3 in 8% titania base on inside, 8% rutile base on outside.

Ready for Glaze

6-7-07  19th Firing

Setup Result Closer Look

Nickel dud refire without additional glaze. Plus 2 - 28 year old ashtrays with the same glaze & 2 strips with William's white liner.

The refire grew more slightly larger crystals. They seem to have nucleated towards the end of the soaks. The ashtrays nucleated well.

On closer examination most crystals started early in the soaks. They are properly proportioned miniatures. They show the halos from the 1000 and 900C soaks. I think the "DUD" status is due to chemical reasons.


6-3-07 18th Firing Results

This firing yielded kind of a mixed bag. I got 2 widely different nickel looks, and the crystals on the Mn - Co glaze are much smaller than expected.

I changed this firing schedule from the previous one in that I increased the rate of cooling between soaks to the fasted the kiln will do, instead of 500C per hour, Also I eliminated the first 1050C hold and replaced it with lower temperature holds at 1000C and 900C. The lower temperature hold made some interesting halos. I think eliminating the first 1050 hold caused fewer crystals to nucleate early in the firing. This helped in the case of the nickel on stained engobe, which in previous tests had been scaled over, but hurt in the case of the Mn - Co glaze because there are significantly fewer crystals than before and no real big ones.

1% green NiO w/ 1% rutile base on red inclusion stain engobe. 1 layer 8% titania base on 2 layers 0.5% CoCO3+ 2% MnO2 in 8% titania base glaze. Same nickel glaze on another clay. Virtually no crystals. I guess it's fitting for such an ugly form.

6-2-07 18th Firing


Sneak Preview  ~250C

My camera wasn't available to photo the setup. It had 8th Grade Formal Dance duty. My daughter Katerina is in the center with the white dress.

She's growing up fast.

The one with nickel on light red inclusion stain engobe may look pretty cool. The other nickel one is a total bomb! I hope it refires better.


5-31-07 More pieces reduced by Chris Groat

3% CuCO3 in 8% rutile base.

This has to be the ugliest thing I've ever made!

Nd2O3 in rutile base.

See 5-17-07 for "before"

See 5-23-07 for "before"


Trash Can Reduction

                  Before After

5-24-07 A night off

5-23-07  17th Firing Results

More work by Chris Groat


Nickel Oxide on left, 2 1/2% Nd2O3 on right.

I think the glaze came out nice (for an amateur!) Seeding did bubkes! I think the 1/2% Fe2O3 did too. Cobalt is just too strong a colorant?
2% Nd2O3 + 1/2% Fe2O3 in 8% rutile base (2 on left), and without Fe2O3  ( 2 on right).

Do spiky crystals on refires come from additional glaze thickness?


5-22-07 Sneak Preview  250C


5-21-07 17th Firing Setup

Attempted seeding before refiring Refires coated with light glaze application with CMC Test tiles: titania and rutile bases with  2% Nd2O3 and 1/2% Fe2O3 "Texas Style" crystals

I didn't particularly care for the way the 2 pieces with 2% NiO, 1/4% CoCO3 came out. The background is kind of bland and there are very few crystals. I tried to seed them by Dremelling slits in the surface and filling them with 50/50 ZnO2 / SiO2 paste. I overglazed  with the same glaze after adding CMC and 1/2% Fe2O3.

5-21-07 16th Firing Results

A range of colorants

This piece is on it's way to Chris Groat for reduction

Nice BIG Texas style crystals

Copper wire inserted in a hole doesn't work too well as a seed

5-20-07  Sneak Preview

220C @ 9:00 pm (92 C / hr.)



Inside: 3% CuCO3, 8% rutile on lip covered by 8% rutile base.

Outside: 2% Nd2O3 in 8% titania base

I like the inside crystals!

I see I should have seeded the nickel glazed pots.


This looks like the first 28 year old piece I've fired that doesn't have mouse bumps all over it.


I was in my studio about 4:00 pm. The kiln was at 1005C on the controlled cool down segment. I realized I'd be burning my fingers late tonight unloading if it kept going and seeing the other 3 people on my firing comparison just turn there kilns off after the crystal soaks, I killed the power by putting it in IDLE. At 6:30 pm it had cooled to 450C - a rate of 222C (432F) per hour. The pieces look OK.


Comparison of firing schedules supplied by several contributors to the Crystalline Glaze Forum (revised 5-30-07).

Graphs Data

I now think:

I can significantly increase the rate of my firing without suffering adverse effects. I followed Ilsley's recommendations on heat up when I established the program. It has served me well in that I have had no pieces blow up or self destruct, but appears much more conservative than others.

I had a brain fart when I programmed my cool down from peak at 500C/hr. I was thinking about the heating rate and didn't want to program up ramps at the fastest rate possible in order to minimize the times the elements were "full on" so as not to stress them more than I had to and get the longest life. This is not an issue on cooling and if I cooled as fast as possible I may get less glaze in the catchers and get more to stick on the pots.

5-19-07 16th Firing Setup

Today's notebook pages

Avril, Is this light rutile?

Kind of tight!

Colorants in today's firing include CuCO3, NiCO3, CoCO3, MnO2 and Nd2O3.

5-17-07 15th Firing Results



5-16-07 Sneak Preview 370C

5-15-07 15th Firing Setup

3% CuCO3 in 8% rutile base and 2 1/2% NiCO3 w/ .4% titania base. Some pieces seeded with zinc oxide / silica paste filled 1/16"dia. x 1/16" deep hole.


5-14-07 See before and after...... Post Fire Reduction by Chris Groat





5-10-07 Clay Comparison

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Recently I had the good fortune of importing many very interesting crystalline glazed pieces from Beijing, China.

The source of all my good fortune---my day (and night, 24 - 7) job. ZIRCAR Ceramics, Inc.
One of my other passions - landscaping, gardening, greens keeping, etc..

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